diff --git a/packages/stream_chat/build.yaml b/packages/stream_chat/build.yaml
index ddbd70dd..d439bddb 100644
--- a/packages/stream_chat/build.yaml
+++ b/packages/stream_chat/build.yaml
@@ -4,5 +4,4 @@ targets:
       json_serializable:
         options:
           explicit_to_json: true
-          field_rename: snake
-          any_map: true
+          field_rename: snake
\ No newline at end of file
diff --git a/packages/stream_chat/example/lib/main.dart b/packages/stream_chat/example/lib/main.dart
index d13dda4c..11e9779f 100644
--- a/packages/stream_chat/example/lib/main.dart
+++ b/packages/stream_chat/example/lib/main.dart
@@ -44,9 +44,9 @@ class StreamExample extends StatelessWidget {
   /// To initialize this example, an instance of
   /// [client] and [channel] is required.
   const StreamExample({
-    Key key,
-    @required this.client,
-    @required this.channel,
+    Key? key,
+    required this.client,
+    required this.channel,
   }) : super(key: key);
 
   /// Instance of [StreamChatClient] we created earlier.
@@ -69,28 +69,31 @@ class StreamExample extends StatelessWidget {
 /// containing the channel name and a [MessageView] displaying recent messages.
 class HomeScreen extends StatelessWidget {
   /// [HomeScreen] is constructed using the [Channel] we defined earlier.
-  const HomeScreen({Key key, @required this.channel}) : super(key: key);
+  const HomeScreen({
+    Key? key,
+    required this.channel,
+  }) : super(key: key);
 
   /// Channel object containing the [Channel.id] we'd like to observe.
   final Channel channel;
 
   @override
   Widget build(BuildContext context) {
-    final messages = channel.state.channelStateStream;
+    final messages = channel.state!.channelStateStream;
     return Scaffold(
       appBar: AppBar(
         title: Text('Channel: ${channel.id}'),
       ),
       body: SafeArea(
-        child: StreamBuilder<ChannelState>(
+        child: StreamBuilder<ChannelState?>(
           stream: messages,
           builder: (
             BuildContext context,
-            AsyncSnapshot<ChannelState> snapshot,
+            AsyncSnapshot<ChannelState?> snapshot,
           ) {
             if (snapshot.hasData && snapshot.data != null) {
               return MessageView(
-                messages: snapshot.data.messages.reversed.toList(),
+                messages: snapshot.data!.messages.reversed.toList(),
                 channel: channel,
               );
             } else if (snapshot.hasError) {
@@ -119,9 +122,9 @@ class HomeScreen extends StatelessWidget {
 class MessageView extends StatefulWidget {
   /// Message takes the latest list of messages and the current channel.
   const MessageView({
-    Key key,
-    @required this.messages,
-    @required this.channel,
+    Key? key,
+    required this.messages,
+    required this.channel,
   }) : super(key: key);
 
   /// List of messages sent in the given channel.
@@ -135,8 +138,8 @@ class MessageView extends StatefulWidget {
 }
 
 class _MessageViewState extends State<MessageView> {
-  TextEditingController _controller;
-  ScrollController _scrollController;
+  late final TextEditingController _controller;
+  late final ScrollController _scrollController;
 
   List<Message> get _messages => widget.messages;
 
@@ -174,12 +177,12 @@ class _MessageViewState extends State<MessageView> {
             reverse: true,
             itemBuilder: (BuildContext context, int index) {
               final item = _messages[index];
-              if (item.user.id == widget.channel.client.uid) {
+              if (item.user?.id == widget.channel.client.uid) {
                 return Align(
                   alignment: Alignment.centerRight,
                   child: Padding(
                     padding: const EdgeInsets.all(8),
-                    child: Text(item.text),
+                    child: Text(item.text ?? ''),
                   ),
                 );
               } else {
@@ -187,7 +190,7 @@ class _MessageViewState extends State<MessageView> {
                   alignment: Alignment.centerLeft,
                   child: Padding(
                     padding: const EdgeInsets.all(8),
-                    child: Text(item.text),
+                    child: Text(item.text ?? ''),
                   ),
                 );
               }
@@ -246,5 +249,5 @@ class _MessageViewState extends State<MessageView> {
 /// Helper extension for quickly retrieving
 /// the current user id from a [StreamChatClient].
 extension on StreamChatClient {
-  String get uid => state.user.id;
+  String get uid => state.user!.id;
 }
diff --git a/packages/stream_chat/example/pubspec.yaml b/packages/stream_chat/example/pubspec.yaml
index 2d010ab6..1b092b3e 100644
--- a/packages/stream_chat/example/pubspec.yaml
+++ b/packages/stream_chat/example/pubspec.yaml
@@ -5,7 +5,7 @@ publish_to: "none"
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
+  sdk: '>=2.12.0 <3.0.0'
 
 dependencies:
   cupertino_icons: ^1.0.0
diff --git a/packages/stream_chat/lib/src/api/channel.dart b/packages/stream_chat/lib/src/api/channel.dart
index aeacaf7d..63fc5595 100644
--- a/packages/stream_chat/lib/src/api/channel.dart
+++ b/packages/stream_chat/lib/src/api/channel.dart
@@ -2,6 +2,7 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:math';
 
+import 'package:collection/collection.dart' show IterableExtension;
 import 'package:dio/dio.dart';
 import 'package:logging/logging.dart';
 import 'package:rxdart/rxdart.dart';
@@ -27,9 +28,9 @@ class Channel {
 
   /// Create a channel client instance from a [ChannelState] object
   Channel.fromState(this._client, ChannelState channelState) {
-    _cid = channelState.channel.cid;
-    _id = channelState.channel.id;
-    type = channelState.channel.type;
+    _cid = channelState.channel!.cid;
+    _id = channelState.channel!.id;
+    type = channelState.channel!.type;
 
     state = ChannelClientState(this, channelState);
     _initializedCompleter.complete(true);
@@ -37,16 +38,16 @@ class Channel {
   }
 
   /// This client state
-  ChannelClientState state;
+  ChannelClientState? state;
 
   /// The channel type
-  String type;
+  String? type;
 
-  String _id;
-  String _cid;
-  Map<String, dynamic> _extraData;
+  String? _id;
+  String? _cid;
+  Map<String, dynamic>? _extraData;
 
-  set extraData(Map<String, dynamic> extraData) {
+  set extraData(Map<String, dynamic>? extraData) {
     if (_initializedCompleter.isCompleted) {
       throw Exception(
           'Once the channel is initialized you should use channel.update '
@@ -58,12 +59,12 @@ class Channel {
   /// Returns true if the channel is muted
   bool get isMuted =>
       _client.state.user?.channelMutes
-          ?.any((element) => element.channel.cid == cid) ==
+          .any((element) => element.channel.cid == cid) ==
       true;
 
   /// Returns true if the channel is muted as a stream
-  Stream<bool> get isMutedStream => _client.state.userStream?.map((event) =>
-      event.channelMutes?.any((element) => element.channel.cid == cid) == true);
+  Stream<bool>? get isMutedStream => _client.state.userStream.map((event) =>
+      event!.channelMutes.any((element) => element.channel.cid == cid) == true);
 
   /// True if the channel is a group
   bool get isGroup => memberCount != 2;
@@ -72,85 +73,130 @@ class Channel {
   bool get isDistinct => id?.startsWith('!members') == true;
 
   /// Channel configuration
-  ChannelConfig get config => state?._channelState?.channel?.config;
+  ChannelConfig? get config {
+    _checkInitialized();
+    return state?._channelState.channel?.config;
+  }
 
   /// Channel configuration as a stream
-  Stream<ChannelConfig> get configStream =>
-      state?.channelStateStream?.map((cs) => cs.channel?.config);
+  Stream<ChannelConfig?>? get configStream {
+    _checkInitialized();
+    return state?.channelStateStream.map((cs) => cs!.channel?.config);
+  }
 
   /// Channel user creator
-  User get createdBy => state?._channelState?.channel?.createdBy;
+  User? get createdBy {
+    _checkInitialized();
+    return state?._channelState.channel?.createdBy;
+  }
 
   /// Channel user creator as a stream
-  Stream<User> get createdByStream =>
-      state?.channelStateStream?.map((cs) => cs.channel?.createdBy);
+  Stream<User?>? get createdByStream {
+    _checkInitialized();
+    return state?.channelStateStream.map((cs) => cs!.channel?.createdBy);
+  }
 
   /// Channel frozen status
-  bool get frozen => state?._channelState?.channel?.frozen;
+  bool? get frozen {
+    _checkInitialized();
+    return state?._channelState.channel?.frozen;
+  }
 
   /// Channel frozen status as a stream
-  Stream<bool> get frozenStream =>
-      state?.channelStateStream?.map((cs) => cs.channel?.frozen);
+  Stream<bool?>? get frozenStream {
+    _checkInitialized();
+    return state?.channelStateStream.map((cs) => cs!.channel?.frozen);
+  }
 
   /// Channel creation date
-  DateTime get createdAt => state?._channelState?.channel?.createdAt;
+  DateTime? get createdAt {
+    _checkInitialized();
+    return state?._channelState.channel?.createdAt;
+  }
 
   /// Channel creation date as a stream
-  Stream<DateTime> get createdAtStream =>
-      state?.channelStateStream?.map((cs) => cs.channel?.createdAt);
+  Stream<DateTime?>? get createdAtStream {
+    _checkInitialized();
+    return state?.channelStateStream.map((cs) => cs!.channel?.createdAt);
+  }
 
   /// Channel last message date
-  DateTime get lastMessageAt => state?._channelState?.channel?.lastMessageAt;
+  DateTime? get lastMessageAt {
+    _checkInitialized();
+
+    return state?._channelState.channel?.lastMessageAt;
+  }
 
   /// Channel last message date as a stream
-  Stream<DateTime> get lastMessageAtStream =>
-      state?.channelStateStream?.map((cs) => cs.channel?.lastMessageAt);
+  Stream<DateTime?>? get lastMessageAtStream {
+    _checkInitialized();
+
+    return state?.channelStateStream.map((cs) => cs!.channel?.lastMessageAt);
+  }
 
   /// Channel updated date
-  DateTime get updatedAt => state?._channelState?.channel?.updatedAt;
+  DateTime? get updatedAt {
+    _checkInitialized();
+
+    return state?._channelState.channel?.updatedAt;
+  }
 
   /// Channel updated date as a stream
-  Stream<DateTime> get updatedAtStream =>
-      state?.channelStateStream?.map((cs) => cs.channel?.updatedAt);
+  Stream<DateTime?>? get updatedAtStream {
+    _checkInitialized();
+
+    return state?.channelStateStream.map((cs) => cs!.channel?.updatedAt);
+  }
 
   /// Channel deletion date
-  DateTime get deletedAt => state?._channelState?.channel?.deletedAt;
+  DateTime? get deletedAt {
+    _checkInitialized();
+
+    return state?._channelState.channel?.deletedAt;
+  }
 
   /// Channel deletion date as a stream
-  Stream<DateTime> get deletedAtStream =>
-      state?.channelStateStream?.map((cs) => cs.channel?.deletedAt);
+  Stream<DateTime?>? get deletedAtStream {
+    _checkInitialized();
+
+    return state?.channelStateStream.map((cs) => cs!.channel?.deletedAt);
+  }
 
   /// Channel member count
-  int get memberCount => state?._channelState?.channel?.memberCount;
+  int? get memberCount {
+    _checkInitialized();
+
+    return state?._channelState.channel?.memberCount;
+  }
 
   /// Channel member count as a stream
-  Stream<int> get memberCountStream =>
-      state?.channelStateStream?.map((cs) => cs.channel?.memberCount);
+  Stream<int?>? get memberCountStream {
+    _checkInitialized();
+
+    return state?.channelStateStream.map((cs) => cs!.channel?.memberCount);
+  }
 
   /// Channel id
-  String get id => state?._channelState?.channel?.id ?? _id;
-
-  /// Channel id as a stream
-  Stream<String> get idStream =>
-      state?.channelStateStream?.map((cs) => cs.channel?.id ?? _id);
+  String? get id => state?._channelState.channel?.id ?? _id;
 
   /// Channel cid
-  String get cid => state?._channelState?.channel?.cid ?? _cid;
+  String? get cid => state?._channelState.channel?.cid ?? _cid;
 
   /// Channel team
-  String get team => state?._channelState?.channel?.team;
-
-  /// Channel cid as a stream
-  Stream<String> get cidStream =>
-      state?.channelStateStream?.map((cs) => cs.channel?.cid ?? _cid);
+  String? get team {
+    _checkInitialized();
+    return state?._channelState.channel?.team;
+  }
 
   /// Channel extra data
-  Map<String, dynamic> get extraData =>
-      state?._channelState?.channel?.extraData ?? _extraData;
+  Map<String, dynamic>? get extraData =>
+      state?._channelState.channel?.extraData ?? _extraData;
 
   /// Channel extra data as a stream
-  Stream<Map<String, dynamic>> get extraDataStream =>
-      state?.channelStateStream?.map((cs) => cs.channel?.extraData);
+  Stream<Map<String, dynamic>?>? get extraDataStream {
+    _checkInitialized();
+    return state?.channelStateStream.map((cs) => cs!.channel?.extraData);
+  }
 
   /// The main Stream chat client
   StreamChatClient get client => _client;
@@ -174,7 +220,7 @@ class Channel {
   /// Optionally, provide a [reason] for the cancellation.
   void cancelAttachmentUpload(
     String attachmentId, {
-    String reason,
+    String? reason,
   }) {
     final cancelToken = _cancelableAttachmentUploadRequest[attachmentId];
     if (cancelToken == null) {
@@ -195,9 +241,8 @@ class Channel {
     String messageId,
     Iterable<String> attachmentIds,
   ) {
-    final message = state.messages.firstWhere(
+    final message = state!.messages.firstWhereOrNull(
       (it) => it.id == messageId,
-      orElse: () => null,
     );
 
     if (message == null) {
@@ -248,13 +293,13 @@ class Channel {
       Future<String> future;
       if (isImage) {
         future = sendImage(
-          it.file,
+          it.file!,
           onSendProgress: onSendProgress,
           cancelToken: cancelToken,
         ).then((it) => it.file);
       } else {
         future = sendFile(
-          it.file,
+          it.file!,
           onSendProgress: onSendProgress,
           cancelToken: cancelToken,
         ).then((it) => it.file);
@@ -283,7 +328,7 @@ class Channel {
           it.copyWith(uploadState: UploadState.failed(error: e.toString())),
         );
       }).whenComplete(() {
-        throttledUpdateAttachment?.cancel();
+        throttledUpdateAttachment.cancel();
         _cancelableAttachmentUploadRequest.remove(it.id);
       });
     })).whenComplete(() {
@@ -297,43 +342,34 @@ class Channel {
   /// Waits for a [_messageAttachmentsUploadCompleter] to complete
   /// before actually sending the message.
   Future<SendMessageResponse> sendMessage(Message message) async {
+    _checkInitialized();
     // Cancelling previous completer in case it's called again in the process
     // Eg. Updating the message while the previous call is in progress.
     _messageAttachmentsUploadCompleter
         .remove(message.id)
         ?.completeError('Message Cancelled');
 
-    final quotedMessage = state?.messages?.firstWhere(
-      (m) => m.id == message?.quotedMessageId,
-      orElse: () => null,
+    final quotedMessage = state!.messages.firstWhereOrNull(
+      (m) => m.id == message.quotedMessageId,
     );
     // ignore: parameter_assignments
     message = message.copyWith(
-      createdAt: message.createdAt ?? DateTime.now(),
+      createdAt: message.createdAt,
       user: _client.state.user,
       quotedMessage: quotedMessage,
       status: MessageSendingStatus.sending,
-      attachments: message.attachments?.map(
+      attachments: message.attachments.map(
         (it) {
           if (it.uploadState.isSuccess) return it;
           return it.copyWith(uploadState: const UploadState.preparing());
         },
-      )?.toList(),
+      ).toList(),
     );
 
-    if (message.parentId != null && message.id == null) {
-      final parentMessage =
-          state.messages.firstWhere((m) => m.id == message.parentId);
-
-      state?.addMessage(parentMessage.copyWith(
-        replyCount: parentMessage.replyCount + 1,
-      ));
-    }
-
-    state?.addMessage(message);
+    state!.addMessage(message);
 
     try {
-      if (message.attachments?.any((it) => !it.uploadState.isSuccess) == true) {
+      if (message.attachments.any((it) => !it.uploadState.isSuccess) == true) {
         final attachmentsUploadCompleter = Completer<Message>();
         _messageAttachmentsUploadCompleter[message.id] =
             attachmentsUploadCompleter;
@@ -348,12 +384,12 @@ class Channel {
         message = await attachmentsUploadCompleter.future;
       }
 
-      final response = await _client.sendMessage(message, id, type);
-      state?.addMessage(response.message);
+      final response = await _client.sendMessage(message, id!, type!);
+      state!.addMessage(response.message);
       return response;
     } catch (error) {
       if (error is DioError && error.type != DioErrorType.response) {
-        state?.retryQueue?.add([message]);
+        state!.retryQueue?.add([message]);
       }
       rethrow;
     }
@@ -372,19 +408,19 @@ class Channel {
     // ignore: parameter_assignments
     message = message.copyWith(
       status: MessageSendingStatus.updating,
-      updatedAt: message.updatedAt ?? DateTime.now(),
-      attachments: message.attachments?.map(
+      updatedAt: message.updatedAt,
+      attachments: message.attachments.map(
         (it) {
           if (it.uploadState.isSuccess) return it;
           return it.copyWith(uploadState: const UploadState.preparing());
         },
-      )?.toList(),
+      ).toList(),
     );
 
     state?.addMessage(message);
 
     try {
-      if (message.attachments?.any((it) => !it.uploadState.isSuccess) == true) {
+      if (message.attachments.any((it) => !it.uploadState.isSuccess) == true) {
         final attachmentsUploadCompleter = Completer<Message>();
         _messageAttachmentsUploadCompleter[message.id] =
             attachmentsUploadCompleter;
@@ -400,9 +436,13 @@ class Channel {
       }
 
       final response = await _client.updateMessage(message);
-      state?.addMessage(response?.message?.copyWith(
+
+      final m = response.message.copyWith(
         ownReactions: message.ownReactions,
-      ));
+      );
+
+      state?.addMessage(m);
+
       return response;
     } catch (error) {
       if (error is DioError && error.type != DioErrorType.response) {
@@ -417,7 +457,7 @@ class Channel {
     // Directly deleting the local messages which are not yet sent to server
     if (message.status == MessageSendingStatus.sending ||
         message.status == MessageSendingStatus.failed) {
-      state.addMessage(message.copyWith(
+      state!.addMessage(message.copyWith(
         type: 'deleted',
         status: MessageSendingStatus.sent,
       ));
@@ -456,18 +496,18 @@ class Channel {
   /// Pins provided message
   Future<UpdateMessageResponse> pinMessage(
     Message message,
-    Object timeoutOrExpirationDate,
+    Object? timeoutOrExpirationDate,
   ) {
     assert(() {
       if (timeoutOrExpirationDate is! DateTime &&
-          timeoutOrExpirationDate is! num &&
-          timeoutOrExpirationDate != null) {
+          timeoutOrExpirationDate != null &&
+          timeoutOrExpirationDate is! num) {
         throw ArgumentError('Invalid timeout or Expiration date');
       }
       return true;
     }(), 'Check for invalid token or expiration date');
 
-    DateTime pinExpires;
+    DateTime? pinExpires;
     if (timeoutOrExpirationDate is DateTime) {
       pinExpires = timeoutOrExpirationDate;
     } else if (timeoutOrExpirationDate is num) {
@@ -490,37 +530,41 @@ class Channel {
   /// Send a file to this channel
   Future<SendFileResponse> sendFile(
     AttachmentFile file, {
-    ProgressCallback onSendProgress,
-    CancelToken cancelToken,
-  }) =>
-      _client.sendFile(
-        file,
-        id,
-        type,
-        onSendProgress: onSendProgress,
-        cancelToken: cancelToken,
-      );
+    ProgressCallback? onSendProgress,
+    CancelToken? cancelToken,
+  }) {
+    _checkInitialized();
+    return _client.sendFile(
+      file,
+      id!,
+      type!,
+      onSendProgress: onSendProgress,
+      cancelToken: cancelToken,
+    );
+  }
 
   /// Send an image to this channel
   Future<SendImageResponse> sendImage(
     AttachmentFile file, {
-    ProgressCallback onSendProgress,
-    CancelToken cancelToken,
-  }) =>
-      _client.sendImage(
-        file,
-        id,
-        type,
-        onSendProgress: onSendProgress,
-        cancelToken: cancelToken,
-      );
+    ProgressCallback? onSendProgress,
+    CancelToken? cancelToken,
+  }) {
+    _checkInitialized();
+    return _client.sendImage(
+      file,
+      id!,
+      type!,
+      onSendProgress: onSendProgress,
+      cancelToken: cancelToken,
+    );
+  }
 
   /// A message search.
   Future<SearchMessagesResponse> search({
-    String query,
-    Map<String, dynamic> messageFilters,
-    List<SortOption> sort,
-    PaginationParams paginationParams,
+    String? query,
+    Map<String, dynamic>? messageFilters,
+    List<SortOption>? sort,
+    PaginationParams? paginationParams,
   }) =>
       _client.search(
         {
@@ -537,16 +581,30 @@ class Channel {
   /// Delete a file from this channel
   Future<EmptyResponse> deleteFile(
     String url, {
-    CancelToken cancelToken,
-  }) =>
-      _client.deleteFile(url, id, type, cancelToken: cancelToken);
+    CancelToken? cancelToken,
+  }) {
+    _checkInitialized();
+    return _client.deleteFile(
+      url,
+      id!,
+      type!,
+      cancelToken: cancelToken,
+    );
+  }
 
   /// Delete an image from this channel
   Future<EmptyResponse> deleteImage(
     String url, {
-    CancelToken cancelToken,
-  }) =>
-      _client.deleteImage(url, id, type, cancelToken: cancelToken);
+    CancelToken? cancelToken,
+  }) {
+    _checkInitialized();
+    return _client.deleteImage(
+      url,
+      id!,
+      type!,
+      cancelToken: cancelToken,
+    );
+  }
 
   /// Send an event on this channel
   Future<EmptyResponse> sendEvent(Event event) {
@@ -554,7 +612,7 @@ class Channel {
     return _client.post(
       '$_channelURL/event',
       data: {'event': event.toJson()},
-    ).then((res) => _client.decode(res.data, EmptyResponse.fromJson));
+    ).then((res) => _client.decode(res.data, EmptyResponse.fromJson)!);
   }
 
   /// Send a reaction to this channel
@@ -565,20 +623,21 @@ class Channel {
     Map<String, dynamic> extraData = const {},
     bool enforceUnique = false,
   }) async {
+    _checkInitialized();
     final messageId = message.id;
     final now = DateTime.now();
     final user = _client.state.user;
 
     final latestReactions = [...message.latestReactions ?? <Reaction>[]];
     if (enforceUnique) {
-      latestReactions.removeWhere((it) => it.userId == user.id);
+      latestReactions.removeWhere((it) => it.userId == user!.id);
     }
 
     final newReaction = Reaction(
       messageId: messageId,
       createdAt: now,
       type: type,
-      user: user,
+      user: user!,
       score: 1,
       extraData: extraData,
     );
@@ -589,7 +648,7 @@ class Channel {
       ..removeWhere((it) => it.userId != user.id);
 
     final newMessage = message.copyWith(
-      reactionCounts: {...message?.reactionCounts ?? <String, int>{}}
+      reactionCounts: {...message.reactionCounts ?? <String, int>{}}
         ..update(type, (value) {
           if (enforceUnique) return value;
           return value + 1;
@@ -649,8 +708,8 @@ class Channel {
           r.type == reaction.type &&
           r.messageId == reaction.messageId);
 
-    final ownReactions = [...latestReactions ?? <Reaction>[]]
-      ..removeWhere((it) => it.userId != user.id);
+    final ownReactions = [...latestReactions]
+      ..removeWhere((it) => it.userId != user!.id);
 
     final newMessage = message.copyWith(
       reactionCounts: reactionCounts..removeWhere((_, value) => value == 0),
@@ -675,7 +734,7 @@ class Channel {
   /// Edit the channel custom data
   Future<UpdateChannelResponse> update(
     Map<String, dynamic> channelData, [
-    Message updateMessage,
+    Message? updateMessage,
   ]) async {
     final response = await _client.post(_channelURL, data: {
       if (updateMessage != null)
@@ -705,14 +764,14 @@ class Channel {
   }
 
   /// Accept invitation to the channel
-  Future<AcceptInviteResponse> acceptInvite([Message message]) async {
+  Future<AcceptInviteResponse> acceptInvite([Message? message]) async {
     final res = await _client.post(_channelURL,
         data: {'accept_invite': true, 'message': message?.toJson()});
     return _client.decode(res.data, AcceptInviteResponse.fromJson);
   }
 
   /// Reject invitation to the channel
-  Future<RejectInviteResponse> rejectInvite([Message message]) async {
+  Future<RejectInviteResponse> rejectInvite([Message? message]) async {
     final res = await _client.post(_channelURL,
         data: {'reject_invite': true, 'message': message?.toJson()});
     return _client.decode(res.data, RejectInviteResponse.fromJson);
@@ -721,7 +780,7 @@ class Channel {
   /// Add members to the channel
   Future<AddMembersResponse> addMembers(
     List<String> memberIds, [
-    Message message,
+    Message? message,
   ]) async {
     final res = await _client.post(_channelURL, data: {
       'add_members': memberIds,
@@ -733,7 +792,7 @@ class Channel {
   /// Invite members to the channel
   Future<InviteMembersResponse> inviteMembers(
     List<String> memberIds, [
-    Message message,
+    Message? message,
   ]) async {
     final res = await _client.post(_channelURL, data: {
       'invites': memberIds,
@@ -745,7 +804,7 @@ class Channel {
   /// Remove members from the channel
   Future<RemoveMembersResponse> removeMembers(
     List<String> memberIds, [
-    Message message,
+    Message? message,
   ]) async {
     final res = await _client.post(_channelURL, data: {
       'remove_members': memberIds,
@@ -772,31 +831,30 @@ class Channel {
     final res = _client.decode(response.data, SendActionResponse.fromJson);
 
     if (res.message != null) {
-      state.addMessage(res.message);
+      state!.addMessage(res.message!);
     } else {
-      final oldIndex = state.messages?.indexWhere((m) => m.id == messageId);
+      final oldIndex = state!.messages.indexWhere((m) => m.id == messageId);
 
-      Message oldMessage;
-      if (oldIndex != null && oldIndex != -1) {
-        oldMessage = state.messages[oldIndex];
-        state.updateChannelState(state._channelState.copyWith(
-          messages: state.messages..remove(oldMessage),
+      Message? oldMessage;
+      if (oldIndex != -1) {
+        oldMessage = state!.messages[oldIndex];
+        state!.updateChannelState(state!._channelState.copyWith(
+          messages: state?.messages?..remove(oldMessage),
         ));
       } else {
-        oldMessage = state.threads.values
+        oldMessage = state!.threads!.values
             .expand((messages) => messages)
-            .firstWhere((m) => m.id == messageId, orElse: () => null);
+            .firstWhereOrNull((m) => m.id == messageId);
         if (oldMessage?.parentId != null) {
-          final parentMessage = state.messages.firstWhere(
-            (element) => element.id == oldMessage.parentId,
-            orElse: () => null,
+          final parentMessage = state!.messages.firstWhereOrNull(
+            (element) => element.id == oldMessage!.parentId,
           );
           if (parentMessage != null) {
-            state.addMessage(parentMessage.copyWith(
-                replyCount: parentMessage.replyCount - 1));
+            state!.addMessage(parentMessage.copyWith(
+                replyCount: parentMessage.replyCount! - 1));
           }
-          state.updateThreadInfo(oldMessage.parentId,
-              state.threads[oldMessage.parentId]..remove(oldMessage));
+          state!.updateThreadInfo(oldMessage!.parentId,
+              state!.threads![oldMessage.parentId!]!..remove(oldMessage));
         }
       }
 
@@ -809,9 +867,9 @@ class Channel {
   /// Mark all channel messages as read
   Future<EmptyResponse> markRead() async {
     _checkInitialized();
-    client.state.totalUnreadCount =
-        max(0, (client.state.totalUnreadCount ?? 0) - (state.unreadCount ?? 0));
-    state._unreadCountController.add(0);
+    client.state.totalUnreadCount = max(
+        0, (client.state.totalUnreadCount ?? 0) - (state!.unreadCount ?? 0));
+    state!._unreadCountController.add(0);
     final response = await _client.post('$_channelURL/read', data: {});
     return _client.decode(response.data, EmptyResponse.fromJson);
   }
@@ -845,7 +903,7 @@ class Channel {
 
   void _initState(ChannelState channelState) {
     state = ChannelClientState(this, channelState);
-    client.state.channels[cid] = this;
+    client.state.channels![cid] = this;
     if (!_initializedCompleter.isCompleted) {
       _initializedCompleter.complete(true);
     }
@@ -857,7 +915,7 @@ class Channel {
       '$_channelURL/stop-watching',
       data: {},
     );
-    return _client.decode(response?.data, EmptyResponse.fromJson);
+    return _client.decode(response.data, EmptyResponse.fromJson);
   }
 
   /// List the message replies for a parent message
@@ -918,7 +976,9 @@ class Channel {
       GetMessagesByIdResponse.fromJson,
     );
 
-    state?.updateChannelState(ChannelState(messages: res.messages));
+    final messages = res.messages;
+
+    state?.updateChannelState(ChannelState(messages: messages));
 
     return res;
   }
@@ -952,9 +1012,9 @@ class Channel {
   /// in the offline storage
   Future<ChannelState> query({
     Map<String, dynamic> options = const {},
-    PaginationParams messagesPagination,
-    PaginationParams membersPagination,
-    PaginationParams watchersPagination,
+    PaginationParams? messagesPagination,
+    PaginationParams? membersPagination,
+    PaginationParams? watchersPagination,
     bool preferOffline = false,
   }) async {
     var path = '/channels/$type';
@@ -984,11 +1044,11 @@ class Channel {
 
     if (preferOffline && cid != null) {
       final updatedState =
-          await _client.chatPersistenceClient?.getChannelStateByCid(
-        cid,
+          (await _client.chatPersistenceClient?.getChannelStateByCid(
+        cid!,
         messagePagination: messagesPagination,
-      );
-      if (updatedState != null && updatedState.messages.isNotEmpty) {
+      ))!;
+      if (updatedState.messages.isNotEmpty) {
         if (state == null) {
           _initState(updatedState);
         } else {
@@ -1003,8 +1063,8 @@ class Channel {
       final updatedState = _client.decode(response.data, ChannelState.fromJson);
 
       if (_id == null) {
-        _id = updatedState.channel.id;
-        _cid = updatedState.channel.cid;
+        _id = updatedState.channel!.id;
+        _cid = updatedState.channel!.cid;
       }
 
       state?.updateChannelState(updatedState);
@@ -1013,8 +1073,8 @@ class Channel {
       if (!_client.persistenceEnabled) {
         rethrow;
       }
-      return _client.chatPersistenceClient?.getChannelStateByCid(
-        cid,
+      return _client.chatPersistenceClient!.getChannelStateByCid(
+        cid!,
         messagePagination: messagesPagination,
       );
     }
@@ -1022,9 +1082,9 @@ class Channel {
 
   /// Query channel members
   Future<QueryMembersResponse> queryMembers({
-    Map<String, dynamic> filter,
-    List<SortOption> sort,
-    PaginationParams pagination,
+    Map<String, dynamic>? filter,
+    List<SortOption>? sort,
+    PaginationParams? pagination,
   }) async {
     final payload = <String, dynamic>{
       'sort': sort,
@@ -1038,8 +1098,8 @@ class Channel {
 
     if (id != null) {
       payload['id'] = id;
-    } else if (state?.members?.isNotEmpty == true) {
-      payload['members'] = state.members;
+    } else if (state?.members.isNotEmpty == true) {
+      payload['members'] = state!.members;
     }
 
     final rawRes = await _client.get('/members', queryParameters: {
@@ -1050,7 +1110,7 @@ class Channel {
   }
 
   /// Mutes the channel
-  Future<EmptyResponse> mute({Duration expiration}) async {
+  Future<EmptyResponse> mute({Duration? expiration}) async {
     final response = await _client.post('/moderation/mute/channel', data: {
       'channel_cid': cid,
       if (expiration != null) 'expiration': expiration.inMilliseconds,
@@ -1121,8 +1181,11 @@ class Channel {
         .post('$_channelURL/hide', data: {'clear_history': clearHistory});
 
     if (clearHistory == true) {
-      state.truncate();
-      await _client.chatPersistenceClient?.deleteMessageByCid(_cid);
+      state!.truncate();
+      final cid = _cid;
+      if (cid != null) {
+        await _client.chatPersistenceClient?.deleteMessageByCid(cid);
+      }
     }
 
     return _client.decode(response.data, EmptyResponse.fromJson);
@@ -1139,10 +1202,10 @@ class Channel {
   /// channel. Pass an eventType as parameter in order to filter just a type
   /// of event
   Stream<Event> on([
-    String eventType,
-    String eventType2,
-    String eventType3,
-    String eventType4,
+    String? eventType,
+    String? eventType2,
+    String? eventType3,
+    String? eventType4,
   ]) =>
       _client
           .on(
@@ -1153,11 +1216,11 @@ class Channel {
           )
           .where((e) => e.cid == cid);
 
-  DateTime _lastTypingEvent;
+  DateTime? _lastTypingEvent;
 
   /// First of the [EventType.typingStart] and [EventType.typingStop] events
   /// based on the users keystrokes. Call this on every keystroke.
-  Future<void> keyStroke([String parentId]) async {
+  Future<void> keyStroke([String? parentId]) async {
     if (config?.typingEvents == false) {
       return;
     }
@@ -1166,7 +1229,7 @@ class Channel {
     final now = DateTime.now();
 
     if (_lastTypingEvent == null ||
-        now.difference(_lastTypingEvent).inSeconds >= 2) {
+        now.difference(_lastTypingEvent!).inSeconds >= 2) {
       _lastTypingEvent = now;
       await sendEvent(Event(
         type: EventType.typingStart,
@@ -1176,7 +1239,7 @@ class Channel {
   }
 
   /// Sets last typing to null and sends the typing.stop event
-  Future<void> stopTyping([String parentId]) async {
+  Future<void> stopTyping([String? parentId]) async {
     if (config?.typingEvents == false) {
       return;
     }
@@ -1191,15 +1254,15 @@ class Channel {
 
   /// Call this method to dispose the channel client
   void dispose() {
-    state.dispose();
+    state?.dispose();
   }
 
   void _checkInitialized() {
-    if (!_initializedCompleter.isCompleted) {
-      throw Exception(
-          "Channel $cid hasn't been initialized yet. Make sure to call .watch()"
-          ' or to instantiate the client using [Channel.fromState]');
-    }
+    assert(
+      _initializedCompleter.isCompleted,
+      "Channel $cid hasn't been initialized yet. Make sure to call .watch()"
+      ' or to instantiate the client using [Channel.fromState]',
+    );
   }
 }
 
@@ -1211,7 +1274,7 @@ class ChannelClientState {
     ChannelState channelState,
     //ignore: unnecessary_parenthesis
   ) : _debouncedUpdatePersistenceChannelState = ((ChannelState state) =>
-                _channel?._client?.chatPersistenceClient
+                _channel._client.chatPersistenceClient
                     ?.updateChannelState(state))
             .debounced(const Duration(seconds: 1)) {
     retryQueue = RetryQueue(
@@ -1252,13 +1315,13 @@ class ChannelClientState {
     _startCleaningPinnedMessages();
 
     _channel._client.chatPersistenceClient
-        ?.getChannelThreads(_channel.cid)
-        ?.then((threads) {
+        ?.getChannelThreads(_channel.cid!)
+        .then((threads) {
       _threads = threads;
-    })?.then((_) {
+    }).then((_) {
       _channel._client.chatPersistenceClient
-          ?.getChannelStateByCid(_channel.cid)
-          ?.then((state) {
+          ?.getChannelStateByCid(_channel.cid!)
+          .then((state) {
         // Replacing the persistence state members with the latest
         // `channelState.members` as they may have changes over the time.
         updateChannelState(state.copyWith(members: channelState.members));
@@ -1270,21 +1333,20 @@ class ChannelClientState {
   final _subscriptions = <StreamSubscription>[];
 
   void _computeInitialUnread() {
-    final userRead = channelState?.read?.firstWhere(
-      (r) => r.user.id == _channel._client.state?.user?.id,
-      orElse: () => null,
+    final userRead = channelState?.read.firstWhereOrNull(
+      (r) => r.user.id == _channel._client.state.user?.id,
     );
     if (userRead != null) {
-      _unreadCountController.add(userRead.unreadMessages ?? 0);
+      _unreadCountController.add(userRead.unreadMessages);
     }
   }
 
   void _checkExpiredAttachmentMessages(ChannelState channelState) {
     final expiredAttachmentMessagesId = channelState.messages
-        ?.where((m) =>
+        .where((m) =>
             !_updatedMessagesIds.contains(m.id) &&
-            m.attachments?.isNotEmpty == true &&
-            m.attachments?.any((e) {
+            m.attachments.isNotEmpty == true &&
+            m.attachments.any((e) {
                   final url = e.imageUrl ?? e.assetUrl;
                   if (url == null || !url.contains('')) {
                     return false;
@@ -1295,13 +1357,13 @@ class ChannelClientState {
                     return false;
                   }
                   final expiration =
-                      DateTime.parse(uri.queryParameters['Expires']);
+                      DateTime.parse(uri.queryParameters['Expires']!);
                   return expiration.isBefore(DateTime.now());
                 }) ==
                 true)
-        ?.map((e) => e.id)
-        ?.toList();
-    if (expiredAttachmentMessagesId?.isNotEmpty == true) {
+        .map((e) => e.id)
+        .toList();
+    if (expiredAttachmentMessagesId.isNotEmpty == true) {
       _channel.getMessagesById(expiredAttachmentMessagesId);
       _updatedMessagesIds.addAll(expiredAttachmentMessagesId);
     }
@@ -1310,10 +1372,10 @@ class ChannelClientState {
   void _listenMemberAdded() {
     _subscriptions.add(_channel.on(EventType.memberAdded).listen((Event e) {
       final member = e.member;
-      updateChannelState(channelState.copyWith(
+      updateChannelState(channelState!.copyWith(
         members: [
-          ...channelState.members,
-          member,
+          ...channelState!.members,
+          member!,
         ],
       ));
     }));
@@ -1322,17 +1384,17 @@ class ChannelClientState {
   void _listenMemberRemoved() {
     _subscriptions.add(_channel.on(EventType.memberRemoved).listen((Event e) {
       final user = e.user;
-      updateChannelState(channelState.copyWith(
+      updateChannelState(channelState!.copyWith(
         members: List.from(
-            channelState.members..removeWhere((m) => m.userId == user.id)),
+            channelState!.members..removeWhere((m) => m.userId == user!.id)),
       ));
     }));
   }
 
   void _listenChannelUpdated() {
     _subscriptions.add(_channel.on(EventType.channelUpdated).listen((Event e) {
-      final channel = e.channel;
-      updateChannelState(channelState.copyWith(
+      final channel = e.channel!;
+      updateChannelState(channelState!.copyWith(
         channel: channel,
         members: channel.members,
       ));
@@ -1343,7 +1405,7 @@ class ChannelClientState {
     _subscriptions.add(_channel
         .on(EventType.channelTruncated, EventType.notificationChannelTruncated)
         .listen((event) async {
-      final channel = event.channel;
+      final channel = event.channel!;
       await _channel._client.chatPersistenceClient
           ?.deleteMessageByCid(channel.cid);
       truncate();
@@ -1354,26 +1416,25 @@ class ChannelClientState {
   /// This flag should be managed by UI sdks.
   /// When false, any new message (received by WebSocket event
   /// - [EventType.messageNew]) will not be pushed on to message list.
-  bool get isUpToDate => _isUpToDateController.value;
+  bool get isUpToDate => _isUpToDateController.value!;
 
   set isUpToDate(bool isUpToDate) => _isUpToDateController.add(isUpToDate);
 
   /// [isUpToDate] flag count as a stream
-  Stream<bool> get isUpToDateStream => _isUpToDateController.stream;
+  Stream<bool?> get isUpToDateStream => _isUpToDateController.stream;
 
-  final BehaviorSubject<bool> _isUpToDateController =
+  final BehaviorSubject<bool?> _isUpToDateController =
       BehaviorSubject.seeded(true);
 
   /// The retry queue associated to this channel
-  RetryQueue retryQueue;
+  RetryQueue? retryQueue;
 
   /// Retry failed message
   Future<void> retryFailedMessages() async {
     final failedMessages =
-        <Message>[...messages, ...threads.values.expand((v) => v)]
+        <Message>[...messages, ...threads!.values.expand((v) => v)]
             .where(
               (message) =>
-                  message.status != null &&
                   message.status != MessageSendingStatus.sent &&
                   message.createdAt.isBefore(
                     DateTime.now().subtract(
@@ -1385,14 +1446,14 @@ class ChannelClientState {
             )
             .toList();
 
-    retryQueue.add(failedMessages);
+    retryQueue!.add(failedMessages);
   }
 
   void _listenReactionDeleted() {
     _subscriptions.add(_channel.on(EventType.reactionDeleted).listen((event) {
-      final userId = _channel.client.state.user.id;
-      final message = event.message.copyWith(
-        ownReactions: [...event.message.latestReactions]
+      final userId = _channel.client.state.user!.id;
+      final message = event.message!.copyWith(
+        ownReactions: [...event.message!.latestReactions!]
           ..removeWhere((it) => it.userId != userId),
       );
       addMessage(message);
@@ -1401,9 +1462,9 @@ class ChannelClientState {
 
   void _listenReactions() {
     _subscriptions.add(_channel.on(EventType.reactionNew).listen((event) {
-      final userId = _channel.client.state.user.id;
-      final message = event.message.copyWith(
-        ownReactions: [...event.message.latestReactions]
+      final userId = _channel.client.state.user!.id;
+      final message = event.message!.copyWith(
+        ownReactions: [...event.message!.latestReactions!]
           ..removeWhere((it) => it.userId != userId),
       );
       addMessage(message);
@@ -1417,9 +1478,9 @@ class ChannelClientState {
       EventType.reactionUpdated,
     )
         .listen((event) {
-      final userId = _channel.client.state.user.id;
-      final message = event.message.copyWith(
-        ownReactions: [...event.message.latestReactions]
+      final userId = _channel.client.state.user!.id;
+      final message = event.message!.copyWith(
+        ownReactions: [...event.message!.latestReactions!]
           ..removeWhere((it) => it.userId != userId),
       );
       addMessage(message);
@@ -1427,7 +1488,7 @@ class ChannelClientState {
       if (message.pinned == true) {
         _channelState = _channelState.copyWith(
           pinnedMessages: [
-            ..._channelState.pinnedMessages ?? [],
+            ..._channelState.pinnedMessages,
             message,
           ],
         );
@@ -1437,7 +1498,7 @@ class ChannelClientState {
 
   void _listenMessageDeleted() {
     _subscriptions.add(_channel.on(EventType.messageDeleted).listen((event) {
-      final message = event.message;
+      final message = event.message!;
       addMessage(message);
     }));
   }
@@ -1449,14 +1510,14 @@ class ChannelClientState {
       EventType.notificationMessageNew,
     )
         .listen((event) {
-      final message = event.message;
+      final message = event.message!;
       if (isUpToDate ||
           (message.parentId != null && message.showInChannel != true)) {
         addMessage(message);
       }
 
       if (_countMessageAsUnread(message)) {
-        _unreadCountController.add(_unreadCountController.value + 1);
+        _unreadCountController.add(_unreadCountController.value! + 1);
       }
     }));
   }
@@ -1467,7 +1528,7 @@ class ChannelClientState {
       final newMessages = List<Message>.from(_channelState.messages);
       final oldIndex = newMessages.indexWhere((m) => m.id == message.id);
       if (oldIndex != -1) {
-        Message m;
+        Message? m;
         if (message.quotedMessageId != null && message.quotedMessage == null) {
           final oldMessage = newMessages[oldIndex];
           m = message.copyWith(
@@ -1481,7 +1542,7 @@ class ChannelClientState {
 
       _channelState = _channelState.copyWith(
         messages: newMessages,
-        channel: _channelState.channel.copyWith(
+        channel: _channelState.channel?.copyWith(
           lastMessageAt: message.createdAt,
         ),
       );
@@ -1493,7 +1554,7 @@ class ChannelClientState {
   }
 
   void _listenReadEvents() {
-    if (_channel.config?.readEvents == false) {
+    if (_channelState.channel?.config.readEvents == false) {
       return;
     }
 
@@ -1505,18 +1566,19 @@ class ChannelClientState {
       )
           .listen(
         (event) {
-          final readList = List<Read>.from(_channelState?.read ?? []);
+          final readList = List<Read>.from(_channelState.read);
           final userReadIndex =
-              read?.indexWhere((r) => r.user.id == event.user.id);
+              read?.indexWhere((r) => r.user.id == event.user!.id);
 
           if (userReadIndex != null && userReadIndex != -1) {
             final userRead = readList.removeAt(userReadIndex);
-            if (userRead.user?.id == _channel._client.state.user.id) {
+            if (userRead.user.id == _channel._client.state.user!.id) {
               _unreadCountController.add(0);
             }
             readList.add(Read(
-              user: event.user,
-              lastRead: event.createdAt,
+              user: event.user!,
+              lastRead: event.createdAt!,
+              unreadMessages: event.totalUnreadCount!,
             ));
             _channelState = _channelState.copyWith(read: readList);
           }
@@ -1529,45 +1591,45 @@ class ChannelClientState {
   List<Message> get messages => _channelState.messages;
 
   /// Channel message list as a stream
-  Stream<List<Message>> get messagesStream =>
-      channelStateStream.map((cs) => cs.messages);
+  Stream<List<Message>?> get messagesStream =>
+      channelStateStream.map((cs) => cs!.messages);
 
   /// Channel pinned message list
-  List<Message> get pinnedMessages => _channelState.pinnedMessages?.toList();
+  List<Message>? get pinnedMessages => _channelState.pinnedMessages.toList();
 
   /// Channel pinned message list as a stream
-  Stream<List<Message>> get pinnedMessagesStream =>
-      channelStateStream.map((cs) => cs.pinnedMessages?.toList());
+  Stream<List<Message>?> get pinnedMessagesStream =>
+      channelStateStream.map((cs) => cs!.pinnedMessages.toList());
 
   /// Get channel last message
-  Message get lastMessage => _channelState.messages?.isNotEmpty == true
+  Message? get lastMessage => _channelState.messages.isNotEmpty == true
       ? _channelState.messages.last
       : null;
 
   /// Get channel last message
-  Stream<Message> get lastMessageStream => messagesStream
-      .map((event) => event?.isNotEmpty == true ? event.last : null);
+  Stream<Message?> get lastMessageStream => messagesStream
+      .map((event) => event?.isNotEmpty == true ? event!.last : null);
 
   /// Channel members list
   List<Member> get members => _channelState.members
-      .map((e) => e.copyWith(user: _channel.client.state.users[e.user.id]))
+      .map((e) => e.copyWith(user: _channel.client.state.users[e.user!.id]))
       .toList();
 
   /// Channel members list as a stream
   Stream<List<Member>> get membersStream => CombineLatestStream.combine2<
-          List<Member>, Map<String, User>, List<Member>>(
-        channelStateStream.map((cs) => cs.members),
+          List<Member?>?, Map<String?, User?>, List<Member>>(
+        channelStateStream.map((cs) => cs!.members),
         _channel.client.state.usersStream,
         (members, users) =>
-            members.map((e) => e.copyWith(user: users[e.user.id])).toList(),
+            members!.map((e) => e!.copyWith(user: users[e.user!.id])).toList(),
       );
 
   /// Channel watcher count
-  int get watcherCount => _channelState.watcherCount;
+  int? get watcherCount => _channelState.watcherCount;
 
   /// Channel watcher count as a stream
-  Stream<int> get watcherCountStream =>
-      channelStateStream.map((cs) => cs.watcherCount);
+  Stream<int?> get watcherCountStream =>
+      channelStateStream.map((cs) => cs!.watcherCount);
 
   /// Channel watchers list
   List<User> get watchers => _channelState.watchers
@@ -1575,18 +1637,19 @@ class ChannelClientState {
       .toList();
 
   /// Channel watchers list as a stream
-  Stream<List<User>> get watchersStream =>
-      CombineLatestStream.combine2<List<User>, Map<String, User>, List<User>>(
-        channelStateStream.map((cs) => cs.watchers),
+  Stream<List<User>> get watchersStream => CombineLatestStream.combine2<
+          List<User>?, Map<String?, User?>, List<User>>(
+        channelStateStream.map((cs) => cs!.watchers),
         _channel.client.state.usersStream,
-        (watchers, users) => watchers.map((e) => users[e.id] ?? e).toList(),
+        (watchers, users) => watchers!.map((e) => users[e.id] ?? e).toList(),
       );
 
   /// Channel read list
-  List<Read> get read => _channelState.read;
+  List<Read>? get read => _channelState.read;
 
   /// Channel read list as a stream
-  Stream<List<Read>> get readStream => channelStateStream.map((cs) => cs.read);
+  Stream<List<Read>?> get readStream =>
+      channelStateStream.map((cs) => cs!.read);
 
   final BehaviorSubject<int> _unreadCountController = BehaviorSubject.seeded(0);
 
@@ -1594,36 +1657,36 @@ class ChannelClientState {
   Stream<int> get unreadCountStream => _unreadCountController.stream;
 
   /// Unread count getter
-  int get unreadCount => _unreadCountController.value;
+  int? get unreadCount => _unreadCountController.value;
 
   bool _countMessageAsUnread(Message message) {
-    final userId = _channel.client.state?.user?.id;
-    final userIsMuted = _channel.client.state?.user?.mutes?.firstWhere(
-          (m) => m.user?.id == message.user.id,
-          orElse: () => null,
+    final userId = _channel.client.state.user?.id;
+    final userIsMuted = _channel.client.state.user?.mutes.firstWhereOrNull(
+          (m) => m.user.id == message.user?.id,
         ) !=
         null;
     return message.silent != true &&
         message.shadowed != true &&
-        message.user.id != userId &&
+        message.user?.id != userId &&
         !userIsMuted;
   }
 
   /// Update threads with updated information about messages
-  void updateThreadInfo(String parentId, List<Message> messages) {
-    final newThreads = Map<String, List<Message>>.from(threads);
+  void updateThreadInfo(String? parentId, List<Message>? messages) {
+    final newThreads = Map<String?, List<Message>?>.from(threads!);
 
     if (newThreads.containsKey(parentId)) {
       newThreads[parentId] = [
         ...newThreads[parentId]
-                ?.where(
-                    (newMessage) => !messages.any((m) => m.id == newMessage.id))
-                ?.toList() ??
+                ?.where((newMessage) =>
+                    !messages!.any((m) => m.id == newMessage.id))
+                .toList() ??
             [],
-        ...messages,
+        ...messages!,
       ];
 
-      newThreads[parentId].sort(_sortByCreatedAt);
+      newThreads[parentId]!
+          .sort(_sortByCreatedAt as int Function(Message, Message)?);
     } else {
       newThreads[parentId] = messages;
     }
@@ -1643,40 +1706,37 @@ class ChannelClientState {
   /// Update channelState with updated information
   void updateChannelState(ChannelState updatedState) {
     final newMessages = <Message>[
-      ...updatedState?.messages ?? [],
-      ..._channelState?.messages
-              ?.where((m) =>
-                  updatedState.messages
-                      ?.any((newMessage) => newMessage.id == m.id) !=
-                  true)
-              ?.toList() ??
-          [],
-    ]..sort(_sortByCreatedAt);
+      ...updatedState.messages,
+      ..._channelState.messages
+          .where((m) =>
+              updatedState.messages
+                  .any((newMessage) => newMessage.id == m.id) !=
+              true)
+          .toList(),
+    ]..sort(_sortByCreatedAt as int Function(Message, Message)?);
 
     final newWatchers = <User>[
-      ...updatedState?.watchers ?? [],
-      ..._channelState?.watchers
-              ?.where((w) =>
-                  updatedState.watchers
-                      ?.any((newWatcher) => newWatcher.id == w.id) !=
-                  true)
-              ?.toList() ??
-          [],
+      ...updatedState.watchers,
+      ..._channelState.watchers
+          .where((w) =>
+              updatedState.watchers
+                  .any((newWatcher) => newWatcher.id == w.id) !=
+              true)
+          .toList(),
     ];
 
     final newMembers = <Member>[
-      ...updatedState?.members ?? [],
+      ...updatedState.members,
     ];
 
     final newReads = <Read>[
-      ...updatedState?.read ?? [],
-      ..._channelState?.read
-              ?.where((r) =>
-                  updatedState.read
-                      ?.any((newRead) => newRead.user.id == r.user.id) !=
-                  true)
-              ?.toList() ??
-          [],
+      ...updatedState.read,
+      ..._channelState.read
+          .where((r) =>
+              updatedState.read
+                  .any((newRead) => newRead.user.id == r.user.id) !=
+              true)
+          .toList(),
     ];
 
     _checkExpiredAttachmentMessages(updatedState);
@@ -1692,7 +1752,7 @@ class ChannelClientState {
     );
   }
 
-  int _sortByCreatedAt(a, b) {
+  int? _sortByCreatedAt(a, b) {
     if (a.createdAt == null) {
       return 1;
     }
@@ -1705,52 +1765,54 @@ class ChannelClientState {
   }
 
   /// The channel state related to this client
-  ChannelState get _channelState => _channelStateController.value;
+  ChannelState get _channelState => _channelStateController.value!;
 
   /// The channel state related to this client as a stream
-  Stream<ChannelState> get channelStateStream => _channelStateController.stream;
+  Stream<ChannelState?> get channelStateStream =>
+      _channelStateController.stream;
 
   /// The channel state related to this client
-  ChannelState get channelState => _channelStateController.value;
-  BehaviorSubject<ChannelState> _channelStateController;
+  ChannelState? get channelState => _channelStateController.value;
+  late BehaviorSubject<ChannelState> _channelStateController;
 
   final Debounce _debouncedUpdatePersistenceChannelState;
 
   set _channelState(ChannelState v) {
     _channelStateController.add(v);
-    _debouncedUpdatePersistenceChannelState?.call([v]);
+    _debouncedUpdatePersistenceChannelState.call([v]);
   }
 
   /// The channel threads related to this channel
-  Map<String, List<Message>> get threads => _threadsController.value;
+  Map<String, List<Message>>? get threads => _threadsController.value
+      ?.map((key, value) => MapEntry(key ?? '', value ?? []));
 
   /// The channel threads related to this channel as a stream
-  Stream<Map<String, List<Message>>> get threadsStream =>
+  Stream<Map<String?, List<Message>?>> get threadsStream =>
       _threadsController.stream;
-  final BehaviorSubject<Map<String, List<Message>>> _threadsController =
+  final BehaviorSubject<Map<String?, List<Message>?>> _threadsController =
       BehaviorSubject.seeded({});
 
-  set _threads(Map<String, List<Message>> v) {
+  set _threads(Map<String?, List<Message>?> v) {
     _channel._client.chatPersistenceClient?.updateMessages(
-      _channel.cid,
-      v.values.expand((v) => v).toList(),
+      _channel.cid!,
+      v.values.expand((v) => v!).toList(),
     );
     _threadsController.add(v);
   }
 
   /// Channel related typing users last value
-  List<User> get typingEvents => _typingEventsController.value;
+  List<User>? get typingEvents => _typingEventsController.value as List<User>?;
 
   /// Channel related typing users stream
-  Stream<List<User>> get typingEventsStream => _typingEventsController.stream;
-  final BehaviorSubject<List<User>> _typingEventsController =
+  Stream<List<User?>> get typingEventsStream => _typingEventsController.stream;
+  final BehaviorSubject<List<User?>> _typingEventsController =
       BehaviorSubject.seeded([]);
 
   final Channel _channel;
-  final Map<User, DateTime> _typings = {};
+  final Map<User?, DateTime> _typings = {};
 
   void _listenTypingEvents() {
-    if (_channel.config?.typingEvents == false) {
+    if (_channelState.channel?.config.typingEvents == false) {
       return;
     }
 
@@ -1758,7 +1820,7 @@ class ChannelClientState {
       ..add(
         _channel.on(EventType.typingStart).listen(
           (event) {
-            if (event.user.id != _channel.client.state.user.id) {
+            if (event.user!.id != _channel.client.state.user!.id) {
               _typings[event.user] = DateTime.now();
               _typingEventsController.add(_typings.keys.toList());
             }
@@ -1768,7 +1830,7 @@ class ChannelClientState {
       ..add(
         _channel.on(EventType.typingStop).listen(
           (event) {
-            if (event.user.id != _channel.client.state.user.id) {
+            if (event.user!.id != _channel.client.state.user!.id) {
               _typings.remove(event.user);
               _typingEventsController.add(_typings.keys.toList());
             }
@@ -1780,12 +1842,12 @@ class ChannelClientState {
             .on()
             .where((event) =>
                 event.user != null &&
-                members?.any((m) => m.userId == event.user.id) == true)
+                members.any((m) => m.userId == event.user!.id) == true)
             .listen(
           (event) {
             final newMembers = List<Member>.from(members);
             final oldMemberIndex =
-                newMembers.indexWhere((m) => m.userId == event.user.id);
+                newMembers.indexWhere((m) => m.userId == event.user!.id);
             if (oldMemberIndex > -1) {
               final oldMember = newMembers.removeAt(oldMemberIndex);
               updateChannelState(ChannelState(
@@ -1802,10 +1864,10 @@ class ChannelClientState {
       );
   }
 
-  Timer _cleaningTimer;
+  late Timer _cleaningTimer;
 
   void _startCleaning() {
-    if (_channel.config?.typingEvents == false) {
+    if (_channelState.channel?.config.typingEvents == false) {
       return;
     }
 
@@ -1813,7 +1875,7 @@ class ChannelClientState {
       final now = DateTime.now();
 
       if (_channel._lastTypingEvent != null &&
-          now.difference(_channel._lastTypingEvent).inSeconds > 1) {
+          now.difference(_channel._lastTypingEvent!).inSeconds > 1) {
         _channel.stopTyping();
       }
 
@@ -1821,15 +1883,14 @@ class ChannelClientState {
     });
   }
 
-  Timer _pinnedMessagesTimer;
+  late Timer _pinnedMessagesTimer;
 
   void _startCleaningPinnedMessages() {
     _pinnedMessagesTimer = Timer.periodic(const Duration(seconds: 30), (_) {
       final now = DateTime.now();
-      var expiredMessages = channelState.pinnedMessages
-              ?.where((m) => m.pinExpires?.isBefore(now) == true)
-              ?.toList() ??
-          [];
+      var expiredMessages = channelState!.pinnedMessages
+          .where((m) => m.pinExpires?.isBefore(now) == true)
+          .toList();
       if (expiredMessages.isNotEmpty) {
         expiredMessages = expiredMessages
             .map((m) => m.copyWith(
@@ -1839,7 +1900,7 @@ class ChannelClientState {
             .toList();
 
         updateChannelState(_channelState.copyWith(
-          pinnedMessages: pinnedMessages.where(_pinIsValid()).toList(),
+          pinnedMessages: pinnedMessages!.where(_pinIsValid()).toList(),
           messages: expiredMessages,
         ));
       }
@@ -1863,9 +1924,9 @@ class ChannelClientState {
 
   /// Call this method to dispose this object
   void dispose() {
-    _debouncedUpdatePersistenceChannelState?.cancel();
+    _debouncedUpdatePersistenceChannelState.cancel();
     _unreadCountController.close();
-    retryQueue.dispose();
+    retryQueue!.dispose();
     _subscriptions.forEach((s) => s.cancel());
     _channelStateController.close();
     _isUpToDateController.close();
@@ -1878,5 +1939,5 @@ class ChannelClientState {
 
 bool Function(Message) _pinIsValid() {
   final now = DateTime.now();
-  return (Message m) => m.pinExpires.isAfter(now);
+  return (Message m) => m.pinExpires!.isAfter(now);
 }
diff --git a/packages/stream_chat/lib/src/api/requests.dart b/packages/stream_chat/lib/src/api/requests.dart
index 51151fca..e78a80ec 100644
--- a/packages/stream_chat/lib/src/api/requests.dart
+++ b/packages/stream_chat/lib/src/api/requests.dart
@@ -34,7 +34,7 @@ class SortOption<T> {
 
   /// Sorting field Comparator required for offline sorting
   @JsonKey(ignore: true)
-  final Comparator<T> comparator;
+  final Comparator<T>? comparator;
 
   /// Serialize model to json
   Map<String, dynamic> toJson() => _$SortOptionToJson(this);
@@ -70,31 +70,31 @@ class PaginationParams {
 
   /// Filter on ids greater than the given value.
   @JsonKey(name: 'id_gt')
-  final String greaterThan;
+  final String? greaterThan;
 
   /// Filter on ids greater than or equal to the given value.
   @JsonKey(name: 'id_gte')
-  final String greaterThanOrEqual;
+  final String? greaterThanOrEqual;
 
   /// Filter on ids smaller than the given value.
   @JsonKey(name: 'id_lt')
-  final String lessThan;
+  final String? lessThan;
 
   /// Filter on ids smaller than or equal to the given value.
   @JsonKey(name: 'id_lte')
-  final String lessThanOrEqual;
+  final String? lessThanOrEqual;
 
   /// Serialize model to json
   Map<String, dynamic> toJson() => _$PaginationParamsToJson(this);
 
   /// Creates a copy of [PaginationParams] with specified attributes overridden.
   PaginationParams copyWith({
-    int limit,
-    int offset,
-    String greaterThan,
-    String greaterThanOrEqual,
-    String lessThan,
-    String lessThanOrEqual,
+    int? limit,
+    int? offset,
+    String? greaterThan,
+    String? greaterThanOrEqual,
+    String? lessThan,
+    String? lessThanOrEqual,
   }) =>
       PaginationParams(
         limit: limit ?? this.limit,
@@ -106,6 +106,7 @@ class PaginationParams {
       );
 
   @override
+  @JsonKey(ignore: true)
   int get hashCode =>
       runtimeType.hashCode ^
       limit.hashCode ^
diff --git a/packages/stream_chat/lib/src/api/requests.g.dart b/packages/stream_chat/lib/src/api/requests.g.dart
index f020c1ea..1ec7b5fc 100644
--- a/packages/stream_chat/lib/src/api/requests.g.dart
+++ b/packages/stream_chat/lib/src/api/requests.g.dart
@@ -13,7 +13,10 @@ Map<String, dynamic> _$SortOptionToJson<T>(SortOption<T> instance) =>
     };
 
 Map<String, dynamic> _$PaginationParamsToJson(PaginationParams instance) {
-  final val = <String, dynamic>{};
+  final val = <String, dynamic>{
+    'limit': instance.limit,
+    'offset': instance.offset,
+  };
 
   void writeNotNull(String key, dynamic value) {
     if (value != null) {
@@ -21,8 +24,6 @@ Map<String, dynamic> _$PaginationParamsToJson(PaginationParams instance) {
     }
   }
 
-  writeNotNull('limit', instance.limit);
-  writeNotNull('offset', instance.offset);
   writeNotNull('id_gt', instance.greaterThan);
   writeNotNull('id_gte', instance.greaterThanOrEqual);
   writeNotNull('id_lt', instance.lessThan);
diff --git a/packages/stream_chat/lib/src/api/responses.dart b/packages/stream_chat/lib/src/api/responses.dart
index 431a57e7..a64cd64e 100644
--- a/packages/stream_chat/lib/src/api/responses.dart
+++ b/packages/stream_chat/lib/src/api/responses.dart
@@ -13,14 +13,15 @@ import 'package:stream_chat/src/models/user.dart';
 part 'responses.g.dart';
 
 class _BaseResponse {
-  String duration;
+  String? duration;
 }
 
 /// Model response for [StreamChatClient.resync] api call
 @JsonSerializable(createToJson: false)
 class SyncResponse extends _BaseResponse {
   /// The list of events
-  List<Event> events;
+  @JsonKey(defaultValue: [])
+  late List<Event> events;
 
   /// Create a new instance from a json
   static SyncResponse fromJson(Map<String, dynamic> json) =>
@@ -31,7 +32,8 @@ class SyncResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class QueryChannelsResponse extends _BaseResponse {
   /// List of channels state returned by the query
-  List<ChannelState> channels;
+  @JsonKey(defaultValue: [])
+  late List<ChannelState> channels;
 
   /// Create a new instance from a json
   static QueryChannelsResponse fromJson(Map<String, dynamic> json) =>
@@ -41,8 +43,8 @@ class QueryChannelsResponse extends _BaseResponse {
 /// Model response for [StreamChatClient.queryChannels] api call
 @JsonSerializable(createToJson: false)
 class TranslateMessageResponse extends _BaseResponse {
-  /// List of channels state returned by the query
-  TranslatedMessage message;
+  /// Translated message
+  late TranslatedMessage message;
 
   /// Create a new instance from a json
   static TranslateMessageResponse fromJson(Map<String, dynamic> json) =>
@@ -53,7 +55,8 @@ class TranslateMessageResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class QueryMembersResponse extends _BaseResponse {
   /// List of channels state returned by the query
-  List<Member> members;
+  @JsonKey(defaultValue: [])
+  late List<Member> members;
 
   /// Create a new instance from a json
   static QueryMembersResponse fromJson(Map<String, dynamic> json) =>
@@ -64,7 +67,8 @@ class QueryMembersResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class QueryUsersResponse extends _BaseResponse {
   /// List of users returned by the query
-  List<User> users;
+  @JsonKey(defaultValue: [])
+  late List<User> users;
 
   /// Create a new instance from a json
   static QueryUsersResponse fromJson(Map<String, dynamic> json) =>
@@ -75,7 +79,8 @@ class QueryUsersResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class QueryReactionsResponse extends _BaseResponse {
   /// List of reactions returned by the query
-  List<Reaction> reactions;
+  @JsonKey(defaultValue: [])
+  late List<Reaction> reactions;
 
   /// Create a new instance from a json
   static QueryReactionsResponse fromJson(Map<String, dynamic> json) =>
@@ -86,7 +91,8 @@ class QueryReactionsResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class QueryRepliesResponse extends _BaseResponse {
   /// List of messages returned by the api call
-  List<Message> messages;
+  @JsonKey(defaultValue: [])
+  late List<Message> messages;
 
   /// Create a new instance from a json
   static QueryRepliesResponse fromJson(Map<String, dynamic> json) =>
@@ -97,7 +103,8 @@ class QueryRepliesResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class ListDevicesResponse extends _BaseResponse {
   /// List of user devices
-  List<Device> devices;
+  @JsonKey(defaultValue: [])
+  late List<Device> devices;
 
   /// Create a new instance from a json
   static ListDevicesResponse fromJson(Map<String, dynamic> json) =>
@@ -108,7 +115,7 @@ class ListDevicesResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class SendFileResponse extends _BaseResponse {
   /// The url of the uploaded file
-  String file;
+  late String file;
 
   /// Create a new instance from a json
   static SendFileResponse fromJson(Map<String, dynamic> json) =>
@@ -119,7 +126,7 @@ class SendFileResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class SendImageResponse extends _BaseResponse {
   /// The url of the uploaded file
-  String file;
+  late String file;
 
   /// Create a new instance from a json
   static SendImageResponse fromJson(Map<String, dynamic> json) =>
@@ -130,10 +137,10 @@ class SendImageResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class SendReactionResponse extends _BaseResponse {
   /// Message returned by the api call
-  Message message;
+  late Message message;
 
   /// The reaction created by the api call
-  Reaction reaction;
+  late Reaction reaction;
 
   /// Create a new instance from a json
   static SendReactionResponse fromJson(Map<String, dynamic> json) =>
@@ -144,10 +151,10 @@ class SendReactionResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class ConnectGuestUserResponse extends _BaseResponse {
   /// Guest user access token
-  String accessToken;
+  late String accessToken;
 
   /// Guest user
-  User user;
+  late User user;
 
   /// Create a new instance from a json
   static ConnectGuestUserResponse fromJson(Map<String, dynamic> json) =>
@@ -158,7 +165,8 @@ class ConnectGuestUserResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class UpdateUsersResponse extends _BaseResponse {
   /// Updated users
-  Map<String, User> users;
+  @JsonKey(defaultValue: {})
+  late Map<String, User> users;
 
   /// Create a new instance from a json
   static UpdateUsersResponse fromJson(Map<String, dynamic> json) =>
@@ -169,7 +177,7 @@ class UpdateUsersResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class UpdateMessageResponse extends _BaseResponse {
   /// Message returned by the api call
-  Message message;
+  late Message message;
 
   /// Create a new instance from a json
   static UpdateMessageResponse fromJson(Map<String, dynamic> json) =>
@@ -180,7 +188,7 @@ class UpdateMessageResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class SendMessageResponse extends _BaseResponse {
   /// Message returned by the api call
-  Message message;
+  late Message message;
 
   /// Create a new instance from a json
   static SendMessageResponse fromJson(Map<String, dynamic> json) =>
@@ -191,15 +199,15 @@ class SendMessageResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class GetMessageResponse extends _BaseResponse {
   /// Message returned by the api call
-  Message message;
+  late Message message;
 
   /// Channel of the message
-  ChannelModel channel;
+  ChannelModel? channel;
 
   /// Create a new instance from a json
   static GetMessageResponse fromJson(Map<String, dynamic> json) {
     final res = _$GetMessageResponseFromJson(json);
-    final jsonChannel = res.message?.extraData?.remove('channel');
+    final jsonChannel = res.message.extraData.remove('channel');
     if (jsonChannel != null) {
       res.channel = ChannelModel.fromJson(jsonChannel);
     }
@@ -211,7 +219,8 @@ class GetMessageResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class SearchMessagesResponse extends _BaseResponse {
   /// List of messages returned by the api call
-  List<GetMessageResponse> results;
+  @JsonKey(defaultValue: [])
+  late List<GetMessageResponse> results;
 
   /// Create a new instance from a json
   static SearchMessagesResponse fromJson(Map<String, dynamic> json) =>
@@ -222,7 +231,8 @@ class SearchMessagesResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class GetMessagesByIdResponse extends _BaseResponse {
   /// Message returned by the api call
-  List<Message> messages;
+  @JsonKey(defaultValue: [])
+  late List<Message> messages;
 
   /// Create a new instance from a json
   static GetMessagesByIdResponse fromJson(Map<String, dynamic> json) =>
@@ -233,13 +243,13 @@ class GetMessagesByIdResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class UpdateChannelResponse extends _BaseResponse {
   /// Updated channel
-  ChannelModel channel;
+  late ChannelModel channel;
 
   /// Channel members
-  List<Member> members;
+  List<Member>? members;
 
   /// Message returned by the api call
-  Message message;
+  Message? message;
 
   /// Create a new instance from a json
   static UpdateChannelResponse fromJson(Map<String, dynamic> json) =>
@@ -250,10 +260,10 @@ class UpdateChannelResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class PartialUpdateChannelResponse extends _BaseResponse {
   /// Updated channel
-  ChannelModel channel;
+  late ChannelModel channel;
 
   /// Channel members
-  List<Member> members;
+  List<Member>? members;
 
   /// Create a new instance from a json
   static PartialUpdateChannelResponse fromJson(Map<String, dynamic> json) =>
@@ -264,13 +274,14 @@ class PartialUpdateChannelResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class InviteMembersResponse extends _BaseResponse {
   /// Updated channel
-  ChannelModel channel;
+  late ChannelModel channel;
 
   /// Channel members
-  List<Member> members;
+  @JsonKey(defaultValue: [])
+  late List<Member> members;
 
   /// Message returned by the api call
-  Message message;
+  Message? message;
 
   /// Create a new instance from a json
   static InviteMembersResponse fromJson(Map<String, dynamic> json) =>
@@ -281,13 +292,14 @@ class InviteMembersResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class RemoveMembersResponse extends _BaseResponse {
   /// Updated channel
-  ChannelModel channel;
+  late ChannelModel channel;
 
   /// Channel members
-  List<Member> members;
+  @JsonKey(defaultValue: [])
+  late List<Member> members;
 
   /// Message returned by the api call
-  Message message;
+  Message? message;
 
   /// Create a new instance from a json
   static RemoveMembersResponse fromJson(Map<String, dynamic> json) =>
@@ -298,7 +310,7 @@ class RemoveMembersResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class SendActionResponse extends _BaseResponse {
   /// Message returned by the api call
-  Message message;
+  Message? message;
 
   /// Create a new instance from a json
   static SendActionResponse fromJson(Map<String, dynamic> json) =>
@@ -309,13 +321,14 @@ class SendActionResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class AddMembersResponse extends _BaseResponse {
   /// Updated channel
-  ChannelModel channel;
+  late ChannelModel channel;
 
   /// Channel members
-  List<Member> members;
+  @JsonKey(defaultValue: [])
+  late List<Member> members;
 
   /// Message returned by the api call
-  Message message;
+  Message? message;
 
   /// Create a new instance from a json
   static AddMembersResponse fromJson(Map<String, dynamic> json) =>
@@ -326,13 +339,14 @@ class AddMembersResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class AcceptInviteResponse extends _BaseResponse {
   /// Updated channel
-  ChannelModel channel;
+  late ChannelModel channel;
 
   /// Channel members
-  List<Member> members;
+  @JsonKey(defaultValue: [])
+  late List<Member> members;
 
   /// Message returned by the api call
-  Message message;
+  Message? message;
 
   /// Create a new instance from a json
   static AcceptInviteResponse fromJson(Map<String, dynamic> json) =>
@@ -343,13 +357,14 @@ class AcceptInviteResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class RejectInviteResponse extends _BaseResponse {
   /// Updated channel
-  ChannelModel channel;
+  late ChannelModel channel;
 
   /// Channel members
-  List<Member> members;
+  @JsonKey(defaultValue: [])
+  late List<Member> members;
 
   /// Message returned by the api call
-  Message message;
+  Message? message;
 
   /// Create a new instance from a json
   static RejectInviteResponse fromJson(Map<String, dynamic> json) =>
@@ -368,19 +383,23 @@ class EmptyResponse extends _BaseResponse {
 @JsonSerializable(createToJson: false)
 class ChannelStateResponse extends _BaseResponse {
   /// Updated channel
-  ChannelModel channel;
+  late ChannelModel channel;
 
   /// List of messages returned by the api call
-  List<Message> messages;
+  @JsonKey(defaultValue: [])
+  late List<Message> messages;
 
   /// Channel members
-  List<Member> members;
+  @JsonKey(defaultValue: [])
+  late List<Member> members;
 
   /// Number of users watching the channel
-  int watcherCount;
+  @JsonKey(defaultValue: 0)
+  late int watcherCount;
 
   /// List of read states
-  List<Read> read;
+  @JsonKey(defaultValue: [])
+  late List<Read> read;
 
   /// Create a new instance from a json
   static ChannelStateResponse fromJson(Map<String, dynamic> json) =>
diff --git a/packages/stream_chat/lib/src/api/responses.g.dart b/packages/stream_chat/lib/src/api/responses.g.dart
index 1f290d6e..2358593d 100644
--- a/packages/stream_chat/lib/src/api/responses.g.dart
+++ b/packages/stream_chat/lib/src/api/responses.g.dart
@@ -6,394 +6,274 @@ part of 'responses.dart';
 // JsonSerializableGenerator
 // **************************************************************************
 
-SyncResponse _$SyncResponseFromJson(Map json) {
+SyncResponse _$SyncResponseFromJson(Map<String, dynamic> json) {
   return SyncResponse()
-    ..duration = json['duration'] as String
-    ..events = (json['events'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Event.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList();
+    ..duration = json['duration'] as String?
+    ..events = (json['events'] as List<dynamic>?)
+            ?.map((e) => Event.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [];
 }
 
-QueryChannelsResponse _$QueryChannelsResponseFromJson(Map json) {
+QueryChannelsResponse _$QueryChannelsResponseFromJson(
+    Map<String, dynamic> json) {
   return QueryChannelsResponse()
-    ..duration = json['duration'] as String
-    ..channels = (json['channels'] as List)
-        ?.map((e) => e == null ? null : ChannelState.fromJson(e as Map))
-        ?.toList();
+    ..duration = json['duration'] as String?
+    ..channels = (json['channels'] as List<dynamic>?)
+            ?.map((e) => ChannelState.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [];
 }
 
-TranslateMessageResponse _$TranslateMessageResponseFromJson(Map json) {
+TranslateMessageResponse _$TranslateMessageResponseFromJson(
+    Map<String, dynamic> json) {
   return TranslateMessageResponse()
-    ..duration = json['duration'] as String
-    ..message = json['message'] == null
-        ? null
-        : TranslatedMessage.fromJson((json['message'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ));
+    ..duration = json['duration'] as String?
+    ..message =
+        TranslatedMessage.fromJson(json['message'] as Map<String, dynamic>);
 }
 
-QueryMembersResponse _$QueryMembersResponseFromJson(Map json) {
+QueryMembersResponse _$QueryMembersResponseFromJson(Map<String, dynamic> json) {
   return QueryMembersResponse()
-    ..duration = json['duration'] as String
-    ..members = (json['members'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Member.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList();
+    ..duration = json['duration'] as String?
+    ..members = (json['members'] as List<dynamic>?)
+            ?.map((e) => Member.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [];
 }
 
-QueryUsersResponse _$QueryUsersResponseFromJson(Map json) {
+QueryUsersResponse _$QueryUsersResponseFromJson(Map<String, dynamic> json) {
   return QueryUsersResponse()
-    ..duration = json['duration'] as String
-    ..users = (json['users'] as List)
-        ?.map((e) => e == null
-            ? null
-            : User.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList();
+    ..duration = json['duration'] as String?
+    ..users = (json['users'] as List<dynamic>?)
+            ?.map((e) => User.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [];
 }
 
-QueryReactionsResponse _$QueryReactionsResponseFromJson(Map json) {
+QueryReactionsResponse _$QueryReactionsResponseFromJson(
+    Map<String, dynamic> json) {
   return QueryReactionsResponse()
-    ..duration = json['duration'] as String
-    ..reactions = (json['reactions'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Reaction.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList();
+    ..duration = json['duration'] as String?
+    ..reactions = (json['reactions'] as List<dynamic>?)
+            ?.map((e) => Reaction.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [];
 }
 
-QueryRepliesResponse _$QueryRepliesResponseFromJson(Map json) {
+QueryRepliesResponse _$QueryRepliesResponseFromJson(Map<String, dynamic> json) {
   return QueryRepliesResponse()
-    ..duration = json['duration'] as String
-    ..messages = (json['messages'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Message.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList();
+    ..duration = json['duration'] as String?
+    ..messages = (json['messages'] as List<dynamic>?)
+            ?.map((e) => Message.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [];
 }
 
-ListDevicesResponse _$ListDevicesResponseFromJson(Map json) {
+ListDevicesResponse _$ListDevicesResponseFromJson(Map<String, dynamic> json) {
   return ListDevicesResponse()
-    ..duration = json['duration'] as String
-    ..devices = (json['devices'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Device.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList();
+    ..duration = json['duration'] as String?
+    ..devices = (json['devices'] as List<dynamic>?)
+            ?.map((e) => Device.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [];
 }
 
-SendFileResponse _$SendFileResponseFromJson(Map json) {
+SendFileResponse _$SendFileResponseFromJson(Map<String, dynamic> json) {
   return SendFileResponse()
-    ..duration = json['duration'] as String
+    ..duration = json['duration'] as String?
     ..file = json['file'] as String;
 }
 
-SendImageResponse _$SendImageResponseFromJson(Map json) {
+SendImageResponse _$SendImageResponseFromJson(Map<String, dynamic> json) {
   return SendImageResponse()
-    ..duration = json['duration'] as String
+    ..duration = json['duration'] as String?
     ..file = json['file'] as String;
 }
 
-SendReactionResponse _$SendReactionResponseFromJson(Map json) {
+SendReactionResponse _$SendReactionResponseFromJson(Map<String, dynamic> json) {
   return SendReactionResponse()
-    ..duration = json['duration'] as String
-    ..message = json['message'] == null
-        ? null
-        : Message.fromJson((json['message'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ))
-    ..reaction = json['reaction'] == null
-        ? null
-        : Reaction.fromJson((json['reaction'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ));
+    ..duration = json['duration'] as String?
+    ..message = Message.fromJson(json['message'] as Map<String, dynamic>)
+    ..reaction = Reaction.fromJson(json['reaction'] as Map<String, dynamic>);
 }
 
-ConnectGuestUserResponse _$ConnectGuestUserResponseFromJson(Map json) {
+ConnectGuestUserResponse _$ConnectGuestUserResponseFromJson(
+    Map<String, dynamic> json) {
   return ConnectGuestUserResponse()
-    ..duration = json['duration'] as String
+    ..duration = json['duration'] as String?
     ..accessToken = json['access_token'] as String
-    ..user = json['user'] == null
-        ? null
-        : User.fromJson((json['user'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ));
+    ..user = User.fromJson(json['user'] as Map<String, dynamic>);
 }
 
-UpdateUsersResponse _$UpdateUsersResponseFromJson(Map json) {
+UpdateUsersResponse _$UpdateUsersResponseFromJson(Map<String, dynamic> json) {
   return UpdateUsersResponse()
-    ..duration = json['duration'] as String
-    ..users = (json['users'] as Map)?.map(
-      (k, e) => MapEntry(
-          k as String,
-          e == null
-              ? null
-              : User.fromJson((e as Map)?.map(
-                  (k, e) => MapEntry(k as String, e),
-                ))),
-    );
+    ..duration = json['duration'] as String?
+    ..users = (json['users'] as Map<String, dynamic>?)?.map(
+          (k, e) => MapEntry(k, User.fromJson(e as Map<String, dynamic>)),
+        ) ??
+        {};
 }
 
-UpdateMessageResponse _$UpdateMessageResponseFromJson(Map json) {
+UpdateMessageResponse _$UpdateMessageResponseFromJson(
+    Map<String, dynamic> json) {
   return UpdateMessageResponse()
-    ..duration = json['duration'] as String
-    ..message = json['message'] == null
-        ? null
-        : Message.fromJson((json['message'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ));
+    ..duration = json['duration'] as String?
+    ..message = Message.fromJson(json['message'] as Map<String, dynamic>);
 }
 
-SendMessageResponse _$SendMessageResponseFromJson(Map json) {
+SendMessageResponse _$SendMessageResponseFromJson(Map<String, dynamic> json) {
   return SendMessageResponse()
-    ..duration = json['duration'] as String
-    ..message = json['message'] == null
-        ? null
-        : Message.fromJson((json['message'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ));
+    ..duration = json['duration'] as String?
+    ..message = Message.fromJson(json['message'] as Map<String, dynamic>);
 }
 
-GetMessageResponse _$GetMessageResponseFromJson(Map json) {
+GetMessageResponse _$GetMessageResponseFromJson(Map<String, dynamic> json) {
   return GetMessageResponse()
-    ..duration = json['duration'] as String
-    ..message = json['message'] == null
-        ? null
-        : Message.fromJson((json['message'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ))
+    ..duration = json['duration'] as String?
+    ..message = Message.fromJson(json['message'] as Map<String, dynamic>)
     ..channel = json['channel'] == null
         ? null
-        : ChannelModel.fromJson((json['channel'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ));
+        : ChannelModel.fromJson(json['channel'] as Map<String, dynamic>);
 }
 
-SearchMessagesResponse _$SearchMessagesResponseFromJson(Map json) {
+SearchMessagesResponse _$SearchMessagesResponseFromJson(
+    Map<String, dynamic> json) {
   return SearchMessagesResponse()
-    ..duration = json['duration'] as String
-    ..results = (json['results'] as List)
-        ?.map((e) => e == null ? null : GetMessageResponse.fromJson(e as Map))
-        ?.toList();
+    ..duration = json['duration'] as String?
+    ..results = (json['results'] as List<dynamic>?)
+            ?.map((e) => GetMessageResponse.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [];
 }
 
-GetMessagesByIdResponse _$GetMessagesByIdResponseFromJson(Map json) {
+GetMessagesByIdResponse _$GetMessagesByIdResponseFromJson(
+    Map<String, dynamic> json) {
   return GetMessagesByIdResponse()
-    ..duration = json['duration'] as String
-    ..messages = (json['messages'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Message.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList();
+    ..duration = json['duration'] as String?
+    ..messages = (json['messages'] as List<dynamic>?)
+            ?.map((e) => Message.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [];
 }
 
-UpdateChannelResponse _$UpdateChannelResponseFromJson(Map json) {
+UpdateChannelResponse _$UpdateChannelResponseFromJson(
+    Map<String, dynamic> json) {
   return UpdateChannelResponse()
-    ..duration = json['duration'] as String
-    ..channel = json['channel'] == null
-        ? null
-        : ChannelModel.fromJson((json['channel'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ))
-    ..members = (json['members'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Member.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList()
+    ..duration = json['duration'] as String?
+    ..channel = ChannelModel.fromJson(json['channel'] as Map<String, dynamic>)
+    ..members = (json['members'] as List<dynamic>?)
+        ?.map((e) => Member.fromJson(e as Map<String, dynamic>))
+        .toList()
     ..message = json['message'] == null
         ? null
-        : Message.fromJson((json['message'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ));
+        : Message.fromJson(json['message'] as Map<String, dynamic>);
 }
 
-PartialUpdateChannelResponse _$PartialUpdateChannelResponseFromJson(Map json) {
+PartialUpdateChannelResponse _$PartialUpdateChannelResponseFromJson(
+    Map<String, dynamic> json) {
   return PartialUpdateChannelResponse()
-    ..duration = json['duration'] as String
-    ..channel = json['channel'] == null
-        ? null
-        : ChannelModel.fromJson((json['channel'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ))
-    ..members = (json['members'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Member.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList();
+    ..duration = json['duration'] as String?
+    ..channel = ChannelModel.fromJson(json['channel'] as Map<String, dynamic>)
+    ..members = (json['members'] as List<dynamic>?)
+        ?.map((e) => Member.fromJson(e as Map<String, dynamic>))
+        .toList();
 }
 
-InviteMembersResponse _$InviteMembersResponseFromJson(Map json) {
+InviteMembersResponse _$InviteMembersResponseFromJson(
+    Map<String, dynamic> json) {
   return InviteMembersResponse()
-    ..duration = json['duration'] as String
-    ..channel = json['channel'] == null
-        ? null
-        : ChannelModel.fromJson((json['channel'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ))
-    ..members = (json['members'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Member.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList()
+    ..duration = json['duration'] as String?
+    ..channel = ChannelModel.fromJson(json['channel'] as Map<String, dynamic>)
+    ..members = (json['members'] as List<dynamic>?)
+            ?.map((e) => Member.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        []
     ..message = json['message'] == null
         ? null
-        : Message.fromJson((json['message'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ));
+        : Message.fromJson(json['message'] as Map<String, dynamic>);
 }
 
-RemoveMembersResponse _$RemoveMembersResponseFromJson(Map json) {
+RemoveMembersResponse _$RemoveMembersResponseFromJson(
+    Map<String, dynamic> json) {
   return RemoveMembersResponse()
-    ..duration = json['duration'] as String
-    ..channel = json['channel'] == null
-        ? null
-        : ChannelModel.fromJson((json['channel'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ))
-    ..members = (json['members'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Member.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList()
+    ..duration = json['duration'] as String?
+    ..channel = ChannelModel.fromJson(json['channel'] as Map<String, dynamic>)
+    ..members = (json['members'] as List<dynamic>?)
+            ?.map((e) => Member.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        []
     ..message = json['message'] == null
         ? null
-        : Message.fromJson((json['message'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ));
+        : Message.fromJson(json['message'] as Map<String, dynamic>);
 }
 
-SendActionResponse _$SendActionResponseFromJson(Map json) {
+SendActionResponse _$SendActionResponseFromJson(Map<String, dynamic> json) {
   return SendActionResponse()
-    ..duration = json['duration'] as String
+    ..duration = json['duration'] as String?
     ..message = json['message'] == null
         ? null
-        : Message.fromJson((json['message'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ));
+        : Message.fromJson(json['message'] as Map<String, dynamic>);
 }
 
-AddMembersResponse _$AddMembersResponseFromJson(Map json) {
+AddMembersResponse _$AddMembersResponseFromJson(Map<String, dynamic> json) {
   return AddMembersResponse()
-    ..duration = json['duration'] as String
-    ..channel = json['channel'] == null
-        ? null
-        : ChannelModel.fromJson((json['channel'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ))
-    ..members = (json['members'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Member.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList()
+    ..duration = json['duration'] as String?
+    ..channel = ChannelModel.fromJson(json['channel'] as Map<String, dynamic>)
+    ..members = (json['members'] as List<dynamic>?)
+            ?.map((e) => Member.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        []
     ..message = json['message'] == null
         ? null
-        : Message.fromJson((json['message'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ));
+        : Message.fromJson(json['message'] as Map<String, dynamic>);
 }
 
-AcceptInviteResponse _$AcceptInviteResponseFromJson(Map json) {
+AcceptInviteResponse _$AcceptInviteResponseFromJson(Map<String, dynamic> json) {
   return AcceptInviteResponse()
-    ..duration = json['duration'] as String
-    ..channel = json['channel'] == null
-        ? null
-        : ChannelModel.fromJson((json['channel'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ))
-    ..members = (json['members'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Member.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList()
+    ..duration = json['duration'] as String?
+    ..channel = ChannelModel.fromJson(json['channel'] as Map<String, dynamic>)
+    ..members = (json['members'] as List<dynamic>?)
+            ?.map((e) => Member.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        []
     ..message = json['message'] == null
         ? null
-        : Message.fromJson((json['message'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ));
+        : Message.fromJson(json['message'] as Map<String, dynamic>);
 }
 
-RejectInviteResponse _$RejectInviteResponseFromJson(Map json) {
+RejectInviteResponse _$RejectInviteResponseFromJson(Map<String, dynamic> json) {
   return RejectInviteResponse()
-    ..duration = json['duration'] as String
-    ..channel = json['channel'] == null
-        ? null
-        : ChannelModel.fromJson((json['channel'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ))
-    ..members = (json['members'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Member.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList()
+    ..duration = json['duration'] as String?
+    ..channel = ChannelModel.fromJson(json['channel'] as Map<String, dynamic>)
+    ..members = (json['members'] as List<dynamic>?)
+            ?.map((e) => Member.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        []
     ..message = json['message'] == null
         ? null
-        : Message.fromJson((json['message'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ));
+        : Message.fromJson(json['message'] as Map<String, dynamic>);
 }
 
-EmptyResponse _$EmptyResponseFromJson(Map json) {
-  return EmptyResponse()..duration = json['duration'] as String;
+EmptyResponse _$EmptyResponseFromJson(Map<String, dynamic> json) {
+  return EmptyResponse()..duration = json['duration'] as String?;
 }
 
-ChannelStateResponse _$ChannelStateResponseFromJson(Map json) {
+ChannelStateResponse _$ChannelStateResponseFromJson(Map<String, dynamic> json) {
   return ChannelStateResponse()
-    ..duration = json['duration'] as String
-    ..channel = json['channel'] == null
-        ? null
-        : ChannelModel.fromJson((json['channel'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          ))
-    ..messages = (json['messages'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Message.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList()
-    ..members = (json['members'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Member.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList()
-    ..watcherCount = json['watcher_count'] as int
-    ..read = (json['read'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Read.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList();
+    ..duration = json['duration'] as String?
+    ..channel = ChannelModel.fromJson(json['channel'] as Map<String, dynamic>)
+    ..messages = (json['messages'] as List<dynamic>?)
+            ?.map((e) => Message.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        []
+    ..members = (json['members'] as List<dynamic>?)
+            ?.map((e) => Member.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        []
+    ..watcherCount = json['watcher_count'] as int? ?? 0
+    ..read = (json['read'] as List<dynamic>?)
+            ?.map((e) => Read.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [];
 }
diff --git a/packages/stream_chat/lib/src/api/retry_policy.dart b/packages/stream_chat/lib/src/api/retry_policy.dart
index a4d1e7bd..f0f2c67b 100644
--- a/packages/stream_chat/lib/src/api/retry_policy.dart
+++ b/packages/stream_chat/lib/src/api/retry_policy.dart
@@ -1,4 +1,3 @@
-import 'package:meta/meta.dart';
 import 'package:stream_chat/src/client.dart';
 import 'package:stream_chat/src/exceptions.dart';
 
@@ -6,30 +5,30 @@ import 'package:stream_chat/src/exceptions.dart';
 class RetryPolicy {
   /// Instantiate a new RetryPolicy
   RetryPolicy({
-    @required this.shouldRetry,
-    @required this.retryTimeout,
-    this.attempt,
+    required this.shouldRetry,
+    required this.retryTimeout,
+    this.attempt = 0,
   });
 
   /// The number of attempts tried so far
   int attempt = 0;
 
   /// This function evaluates if we should retry the failure
-  final bool Function(StreamChatClient client, int attempt, ApiError apiError)
+  final bool Function(StreamChatClient client, int attempt, ApiError? apiError)
       shouldRetry;
 
   /// In the case that we want to retry a failed request the retryTimeout
   /// method is called to determine the timeout
   final Duration Function(
-      StreamChatClient client, int attempt, ApiError apiError) retryTimeout;
+      StreamChatClient client, int attempt, ApiError? apiError) retryTimeout;
 
   /// Creates a copy of [RetryPolicy] with specified attributes overridden.
   RetryPolicy copyWith({
-    bool Function(StreamChatClient client, int attempt, ApiError apiError)
+    bool Function(StreamChatClient client, int attempt, ApiError? apiError)?
         shouldRetry,
-    Duration Function(StreamChatClient client, int attempt, ApiError apiError)
+    Duration Function(StreamChatClient client, int attempt, ApiError? apiError)?
         retryTimeout,
-    int attempt,
+    int? attempt,
   }) =>
       RetryPolicy(
         retryTimeout: retryTimeout ?? this.retryTimeout,
diff --git a/packages/stream_chat/lib/src/api/retry_queue.dart b/packages/stream_chat/lib/src/api/retry_queue.dart
index 1049e0e9..c13db9c6 100644
--- a/packages/stream_chat/lib/src/api/retry_queue.dart
+++ b/packages/stream_chat/lib/src/api/retry_queue.dart
@@ -2,7 +2,6 @@ import 'dart:async';
 
 import 'package:collection/collection.dart';
 import 'package:logging/logging.dart';
-import 'package:meta/meta.dart';
 import 'package:stream_chat/src/api/channel.dart';
 import 'package:stream_chat/src/api/retry_policy.dart';
 import 'package:stream_chat/src/event_type.dart';
@@ -14,7 +13,7 @@ import 'package:stream_chat/stream_chat.dart';
 class RetryQueue {
   /// Instantiate a new RetryQueue object
   RetryQueue({
-    @required this.channel,
+    required this.channel,
     this.logger,
   }) {
     _retryPolicy = channel.client.retryPolicy;
@@ -28,14 +27,14 @@ class RetryQueue {
   final Channel channel;
 
   /// The logger associated to this queue
-  final Logger logger;
+  final Logger? logger;
 
   final _subscriptions = <StreamSubscription>[];
 
   void _listenConnectionRecovered() {
     _subscriptions
         .add(channel.client.on(EventType.connectionRecovered).listen((event) {
-      if (!_isRetrying && event.online) {
+      if (!_isRetrying && event.online!) {
         _startRetrying();
       }
     }));
@@ -43,12 +42,13 @@ class RetryQueue {
 
   final HeapPriorityQueue<Message> _messageQueue = HeapPriorityQueue(_byDate);
   bool _isRetrying = false;
-  RetryPolicy _retryPolicy;
+  RetryPolicy? _retryPolicy;
 
   /// Add a list of messages
   void add(List<Message> messages) {
     logger?.info('added ${messages.length} messages');
     final messageList = _messageQueue.toList();
+
     _messageQueue.addAll(messages
         .where((element) => !messageList.any((m) => m.id == element.id)));
 
@@ -60,7 +60,7 @@ class RetryQueue {
   Future<void> _startRetrying() async {
     logger?.info('start retrying');
     _isRetrying = true;
-    final retryPolicy = _retryPolicy.copyWith(attempt: 0);
+    final retryPolicy = _retryPolicy!.copyWith(attempt: 0);
 
     while (_messageQueue.isNotEmpty) {
       final message = _messageQueue.first;
@@ -72,7 +72,7 @@ class RetryQueue {
         logger?.info('now ${_messageQueue.length} messages in the queue');
         retryPolicy.attempt = 0;
       } catch (error) {
-        ApiError apiError;
+        ApiError? apiError;
         if (error is DioError) {
           if (error.type == DioErrorType.response) {
             _messageQueue.remove(message);
@@ -84,7 +84,7 @@ class RetryQueue {
           );
         } else if (error is ApiError) {
           apiError = error;
-          if (apiError.status?.toString()?.startsWith('4') == true) {
+          if (apiError.status?.toString().startsWith('4') == true) {
             _messageQueue.remove(message);
             return;
           }
@@ -101,6 +101,7 @@ class RetryQueue {
         }
 
         retryPolicy.attempt++;
+
         final timeout = retryPolicy.retryTimeout(
           channel.client,
           retryPolicy.attempt,
@@ -112,13 +113,13 @@ class RetryQueue {
     _isRetrying = false;
   }
 
-  void _sendFailedEvent(Message message) {
-    final newStatus = message.status == MessageSendingStatus.sending
+  void _sendFailedEvent(Message? message) {
+    final newStatus = message!.status == MessageSendingStatus.sending
         ? MessageSendingStatus.failed
         : (message.status == MessageSendingStatus.updating
             ? MessageSendingStatus.failed_update
             : MessageSendingStatus.failed_delete);
-    channel.state.addMessage(message.copyWith(
+    channel.state!.addMessage(message.copyWith(
       status: newStatus,
     ));
   }
@@ -141,20 +142,24 @@ class RetryQueue {
       final messageList = _messageQueue.toList();
       if (event.message != null) {
         final messageIndex =
-            messageList.indexWhere((m) => m.id == event.message.id);
+            messageList.indexWhere((m) => m.id == event.message!.id);
         if (messageIndex == -1 &&
             [
               MessageSendingStatus.failed_update,
               MessageSendingStatus.failed,
               MessageSendingStatus.failed_delete,
-            ].contains(event.message.status)) {
+            ].contains(event.message!.status)) {
           logger?.info('add message from events');
-          add([event.message]);
+          final m = event.message;
+
+          if (m != null) {
+            add([m]);
+          }
         } else if (messageIndex != -1 &&
             [
               MessageSendingStatus.sent,
               null,
-            ].contains(event.message.status)) {
+            ].contains(event.message!.status)) {
           _messageQueue.remove(messageList[messageIndex]);
         }
       }
@@ -171,10 +176,14 @@ class RetryQueue {
     final date1 = _getMessageDate(m1);
     final date2 = _getMessageDate(m2);
 
+    if (date1 == null || date2 == null) {
+      return 0;
+    }
+
     return date1.compareTo(date2);
   }
 
-  static DateTime _getMessageDate(Message m1) {
+  static DateTime? _getMessageDate(Message m1) {
     switch (m1.status) {
       case MessageSendingStatus.failed_delete:
       case MessageSendingStatus.deleting:
diff --git a/packages/stream_chat/lib/src/api/web_socket_channel_html.dart b/packages/stream_chat/lib/src/api/web_socket_channel_html.dart
index 9ddd83e5..ab821ca9 100644
--- a/packages/stream_chat/lib/src/api/web_socket_channel_html.dart
+++ b/packages/stream_chat/lib/src/api/web_socket_channel_html.dart
@@ -3,5 +3,5 @@ import 'package:web_socket_channel/web_socket_channel.dart';
 
 /// Html version of websocket implementation
 /// Used in Flutter web version
-WebSocketChannel connectWebSocket(String url, {Iterable<String> protocols}) =>
+WebSocketChannel connectWebSocket(String url, {Iterable<String>? protocols}) =>
     HtmlWebSocketChannel.connect(url, protocols: protocols);
diff --git a/packages/stream_chat/lib/src/api/web_socket_channel_io.dart b/packages/stream_chat/lib/src/api/web_socket_channel_io.dart
index ed37ba7f..8402ca0c 100644
--- a/packages/stream_chat/lib/src/api/web_socket_channel_io.dart
+++ b/packages/stream_chat/lib/src/api/web_socket_channel_io.dart
@@ -3,5 +3,5 @@ import 'package:web_socket_channel/web_socket_channel.dart';
 
 /// IO version of websocket implementation
 /// Used in Flutter mobile version
-WebSocketChannel connectWebSocket(String url, {Iterable<String> protocols}) =>
+WebSocketChannel connectWebSocket(String url, {Iterable<String>? protocols}) =>
     IOWebSocketChannel.connect(url, protocols: protocols);
diff --git a/packages/stream_chat/lib/src/api/web_socket_channel_stub.dart b/packages/stream_chat/lib/src/api/web_socket_channel_stub.dart
index 7e2e47bd..e2efaee6 100644
--- a/packages/stream_chat/lib/src/api/web_socket_channel_stub.dart
+++ b/packages/stream_chat/lib/src/api/web_socket_channel_stub.dart
@@ -3,7 +3,7 @@ import 'package:web_socket_channel/web_socket_channel.dart';
 /// Stub version of websocket implementation
 /// Used just for conditional library import
 WebSocketChannel connectWebSocket(String url,
-        {Iterable<String> protocols,
-        Map<String, dynamic> headers,
-        Duration pingInterval}) =>
+        {Iterable<String>? protocols,
+        Map<String, dynamic>? headers,
+        Duration? pingInterval}) =>
     throw UnimplementedError();
diff --git a/packages/stream_chat/lib/src/api/websocket.dart b/packages/stream_chat/lib/src/api/websocket.dart
index 0f78b1bf..8b670f7f 100644
--- a/packages/stream_chat/lib/src/api/websocket.dart
+++ b/packages/stream_chat/lib/src/api/websocket.dart
@@ -16,8 +16,8 @@ typedef EventHandler = void Function(Event);
 /// Typedef used for connecting to a websocket. Method returns a
 /// [WebSocketChannel] and accepts a connection [url] and an optional
 /// [Iterable] of `protocols`.
-typedef ConnectWebSocket = WebSocketChannel Function(String url,
-    {Iterable<String> protocols});
+typedef ConnectWebSocket = WebSocketChannel Function(String? url,
+    {Iterable<String>? protocols});
 
 // TODO: parse error even
 // TODO: if parsing an error into an event fails we should not hide the
@@ -27,11 +27,11 @@ class WebSocket {
   /// Creates a new websocket
   /// To connect the WS call [connect]
   WebSocket({
-    @required this.baseUrl,
-    this.user,
-    this.connectParams,
-    this.connectPayload,
-    this.handler,
+    required this.baseUrl,
+    required this.user,
+    required this.handler,
+    this.connectParams = const {},
+    this.connectPayload = const {},
     this.logger,
     this.connectFunc,
     this.reconnectionMonitorInterval = 1,
@@ -78,12 +78,12 @@ class WebSocket {
   final EventHandler handler;
 
   /// A WS specific logger instance
-  final Logger logger;
+  final Logger? logger;
 
   /// Connection function
   /// Used only for testing purpose
   @visibleForTesting
-  final ConnectWebSocket connectFunc;
+  final ConnectWebSocket? connectFunc;
 
   /// Interval of the reconnection monitor timer
   /// This checks that it received a new event in the last
@@ -107,43 +107,43 @@ class WebSocket {
       _connectionStatusController.add(status);
 
   /// The current connection status value
-  ConnectionStatus get connectionStatus => _connectionStatusController.value;
+  ConnectionStatus? get connectionStatus => _connectionStatusController.value;
 
   /// This notifies of connection status changes
   Stream<ConnectionStatus> get connectionStatusStream =>
       _connectionStatusController.stream;
 
-  String _path;
+  late final String _path;
   int _retryAttempt = 1;
-  WebSocketChannel _channel;
-  Timer _healthCheck, _reconnectionMonitor;
-  DateTime _lastEventAt;
+  late WebSocketChannel _channel;
+  Timer? _healthCheck, _reconnectionMonitor;
+  DateTime? _lastEventAt;
   bool _manuallyDisconnected = false;
   bool _connecting = false;
   bool _reconnecting = false;
 
   Event _decodeEvent(String source) => Event.fromJson(json.decode(source));
 
-  Completer<Event> _connectionCompleter = Completer<Event>();
+  Completer<Event?> _connectionCompleter = Completer<Event?>();
 
   /// Connect the WS using the parameters passed in the constructor
-  Future<Event> connect() {
+  Future<Event?> connect() async {
     _manuallyDisconnected = false;
 
     if (_connecting) {
-      logger.severe('already connecting');
+      logger?.severe('already connecting');
       return null;
     }
 
     _connecting = true;
     _connectionStatus = ConnectionStatus.connecting;
 
-    logger.info('connecting to $_path');
+    logger?.info('connecting to $_path');
 
     _channel =
         connectFunc?.call(_path) ?? WebSocketChannel.connect(Uri.parse(_path));
     _channel.stream.listen(
-      (data) {
+      (data) async {
         final jsonData = json.decode(data);
         if (jsonData['error'] != null) {
           return _onConnectionError(jsonData['error']);
@@ -153,9 +153,7 @@ class WebSocket {
       onError: (error, stacktrace) {
         _onConnectionError(error, stacktrace);
       },
-      onDone: () {
-        _onDone();
-      },
+      onDone: _onDone,
     );
     return _connectionCompleter.future;
   }
@@ -166,7 +164,7 @@ class WebSocket {
       return;
     }
 
-    logger.info('connection closed | closeCode: ${_channel.closeCode} | '
+    logger?.info('connection closed | closeCode: ${_channel.closeCode} | '
         'closedReason: ${_channel.closeReason}');
 
     if (!_reconnecting) {
@@ -180,10 +178,10 @@ class WebSocket {
     }
 
     final event = _decodeEvent(data);
-    logger.info('received new event: $data');
+    logger?.info('received new event: $data');
 
     if (_lastEventAt == null) {
-      logger.info('connection estabilished');
+      logger?.info('connection estabilished');
       _connecting = false;
       _reconnecting = false;
       _lastEventAt = DateTime.now();
@@ -204,9 +202,9 @@ class WebSocket {
   }
 
   Future<void> _onConnectionError(error, [stacktrace]) async {
-    logger..severe('error connecting')..severe(error);
+    logger?..severe('error connecting')..severe(error);
     if (stacktrace != null) {
-      logger.severe(stacktrace);
+      logger?.severe(stacktrace);
     }
     _connecting = false;
 
@@ -225,7 +223,7 @@ class WebSocket {
   void _reconnectionTimer(_) {
     final now = DateTime.now();
     if (_lastEventAt != null &&
-        now.difference(_lastEventAt).inSeconds > reconnectionMonitorTimeout) {
+        now.difference(_lastEventAt!).inSeconds > reconnectionMonitorTimeout) {
       _channel.sink.close();
     }
   }
@@ -244,18 +242,18 @@ class WebSocket {
       return;
     }
     if (_connecting) {
-      logger.info('already connecting');
+      logger?.info('already connecting');
       return;
     }
 
-    logger.info('reconnecting..');
+    logger?.info('reconnecting..');
 
     _cancelTimers();
 
     try {
       await connect();
     } catch (e) {
-      logger.log(Level.SEVERE, e.toString());
+      logger?.log(Level.SEVERE, e.toString());
     }
     await Future.delayed(
       Duration(seconds: min(_retryAttempt * 5, 25)),
@@ -267,7 +265,7 @@ class WebSocket {
   }
 
   Future<void> _reconnect() async {
-    logger.info('reconnect');
+    logger?.info('reconnect');
     if (!_reconnecting) {
       _reconnecting = true;
       _connectionStatus = ConnectionStatus.connecting;
@@ -279,20 +277,20 @@ class WebSocket {
   void _cancelTimers() {
     _lastEventAt = null;
     if (_healthCheck != null) {
-      _healthCheck.cancel();
+      _healthCheck!.cancel();
     }
     if (_reconnectionMonitor != null) {
-      _reconnectionMonitor.cancel();
+      _reconnectionMonitor!.cancel();
     }
   }
 
   void _healthCheckTimer(_) {
-    logger.info('sending health.check');
+    logger?.info('sending health.check');
     _channel.sink.add("{'type': 'health.check'}");
   }
 
   void _startHealthCheck() {
-    logger.info('start health check monitor');
+    logger?.info('start health check monitor');
 
     _healthCheck = Timer.periodic(
       Duration(seconds: healthCheckInterval),
@@ -311,13 +309,13 @@ class WebSocket {
     if (_manuallyDisconnected) {
       return;
     }
-    logger.info('disconnecting');
+    logger?.info('disconnecting');
     _connectionCompleter = Completer();
     _cancelTimers();
     _reconnecting = false;
     _manuallyDisconnected = true;
     _connectionStatus = ConnectionStatus.disconnected;
     await _connectionStatusController.close();
-    return _channel.sink.close();
+    await _channel.sink.close();
   }
 }
diff --git a/packages/stream_chat/lib/src/attachment_file_uploader.dart b/packages/stream_chat/lib/src/attachment_file_uploader.dart
index 7d9e8c40..d00dd4e7 100644
--- a/packages/stream_chat/lib/src/attachment_file_uploader.dart
+++ b/packages/stream_chat/lib/src/attachment_file_uploader.dart
@@ -1,8 +1,8 @@
 import 'package:dio/dio.dart';
 import 'package:stream_chat/src/api/responses.dart';
 import 'package:stream_chat/src/client.dart';
-import 'package:stream_chat/src/models/attachment_file.dart';
 import 'package:stream_chat/src/extensions/string_extension.dart';
+import 'package:stream_chat/src/models/attachment_file.dart';
 
 /// Class responsible for uploading images and files to a given channel
 abstract class AttachmentFileUploader {
@@ -15,8 +15,8 @@ abstract class AttachmentFileUploader {
     AttachmentFile image,
     String channelId,
     String channelType, {
-    ProgressCallback onSendProgress,
-    CancelToken cancelToken,
+    ProgressCallback? onSendProgress,
+    CancelToken? cancelToken,
   });
 
   /// Uploads a [file] to the given channel.
@@ -28,8 +28,8 @@ abstract class AttachmentFileUploader {
     AttachmentFile file,
     String channelId,
     String channelType, {
-    ProgressCallback onSendProgress,
-    CancelToken cancelToken,
+    ProgressCallback? onSendProgress,
+    CancelToken? cancelToken,
   });
 
   /// Deletes a image using its [url] from the given channel.
@@ -40,7 +40,7 @@ abstract class AttachmentFileUploader {
     String url,
     String channelId,
     String channelType, {
-    CancelToken cancelToken,
+    CancelToken? cancelToken,
   });
 
   /// Deletes a file using its [url] from the given channel.
@@ -51,7 +51,7 @@ abstract class AttachmentFileUploader {
     String url,
     String channelId,
     String channelType, {
-    CancelToken cancelToken,
+    CancelToken? cancelToken,
   });
 }
 
@@ -67,22 +67,22 @@ class StreamAttachmentFileUploader implements AttachmentFileUploader {
     AttachmentFile file,
     String channelId,
     String channelType, {
-    ProgressCallback onSendProgress,
-    CancelToken cancelToken,
+    ProgressCallback? onSendProgress,
+    CancelToken? cancelToken,
   }) async {
-    final filename = file.path?.split('/')?.last ?? file.name;
-    final mimeType = filename.mimeType;
+    final filename = file.path?.split('/').last ?? file.name;
+    final mimeType = filename?.mimeType;
 
-    MultipartFile multiPartFile;
+    MultipartFile? multiPartFile;
     if (file.path != null) {
       multiPartFile = await MultipartFile.fromFile(
-        file.path,
+        file.path!,
         filename: filename,
         contentType: mimeType,
       );
     } else if (file.bytes != null) {
       multiPartFile = MultipartFile.fromBytes(
-        file.bytes,
+        file.bytes!,
         filename: filename,
         contentType: mimeType,
       );
@@ -104,22 +104,22 @@ class StreamAttachmentFileUploader implements AttachmentFileUploader {
     AttachmentFile file,
     String channelId,
     String channelType, {
-    ProgressCallback onSendProgress,
-    CancelToken cancelToken,
+    ProgressCallback? onSendProgress,
+    CancelToken? cancelToken,
   }) async {
-    final filename = file.path?.split('/')?.last ?? file.name;
-    final mimeType = filename.mimeType;
+    final filename = file.path?.split('/').last ?? file.name;
+    final mimeType = filename?.mimeType;
 
-    MultipartFile multiPartFile;
+    MultipartFile? multiPartFile;
     if (file.path != null) {
       multiPartFile = await MultipartFile.fromFile(
-        file.path,
+        file.path!,
         filename: filename,
         contentType: mimeType,
       );
     } else if (file.bytes != null) {
       multiPartFile = MultipartFile.fromBytes(
-        file.bytes,
+        file.bytes!,
         filename: filename,
         contentType: mimeType,
       );
@@ -141,7 +141,7 @@ class StreamAttachmentFileUploader implements AttachmentFileUploader {
     String url,
     String channelId,
     String channelType, {
-    CancelToken cancelToken,
+    CancelToken? cancelToken,
   }) async {
     final response = await _client.delete(
       '/channels/$channelType/$channelId/image',
@@ -156,7 +156,7 @@ class StreamAttachmentFileUploader implements AttachmentFileUploader {
     String url,
     String channelId,
     String channelType, {
-    CancelToken cancelToken,
+    CancelToken? cancelToken,
   }) async {
     final response = await _client.delete(
       '/channels/$channelType/$channelId/file',
diff --git a/packages/stream_chat/lib/src/client.dart b/packages/stream_chat/lib/src/client.dart
index f46ba178..403e5a2b 100644
--- a/packages/stream_chat/lib/src/client.dart
+++ b/packages/stream_chat/lib/src/client.dart
@@ -38,7 +38,7 @@ typedef DecoderFunction<T> = T Function(Map<String, dynamic>);
 
 /// A function which can be used to request a Stream Chat API token from your
 /// own backend server. Function requires a single [userId].
-typedef TokenProvider = Future<String> Function(String userId);
+typedef TokenProvider = Future<String> Function(String? userId);
 
 /// Provider used to send push notifications.
 enum PushProvider {
@@ -82,58 +82,59 @@ class StreamChatClient {
     this.tokenProvider,
     this.baseURL = _defaultBaseURL,
     this.logLevel = Level.WARNING,
-    this.logHandlerFunction,
+    LogHandlerFunction? logHandlerFunction,
     Duration connectTimeout = const Duration(seconds: 6),
     Duration receiveTimeout = const Duration(seconds: 6),
-    Dio httpClient,
-    RetryPolicy retryPolicy,
+    Dio? httpClient,
+    RetryPolicy? retryPolicy,
     this.attachmentFileUploader,
   }) {
     _retryPolicy = retryPolicy ??
         RetryPolicy(
           retryTimeout:
-              (StreamChatClient client, int attempt, ApiError error) =>
+              (StreamChatClient client, int attempt, ApiError? error) =>
                   Duration(seconds: 1 * attempt),
-          shouldRetry: (StreamChatClient client, int attempt, ApiError error) =>
-              attempt < 5,
+          shouldRetry:
+              (StreamChatClient client, int attempt, ApiError? error) =>
+                  attempt < 5,
         );
 
     attachmentFileUploader ??= StreamAttachmentFileUploader(this);
 
     state = ClientState(this);
 
-    _setupLogger();
+    _setupLogger(logHandlerFunction);
     _setupDio(httpClient, receiveTimeout, connectTimeout);
 
     logger.info('instantiating new client');
   }
 
-  set chatPersistenceClient(ChatPersistenceClient value) {
+  set chatPersistenceClient(ChatPersistenceClient? value) {
     _originalChatPersistenceClient = value;
   }
 
-  ChatPersistenceClient _originalChatPersistenceClient;
+  ChatPersistenceClient? _originalChatPersistenceClient;
 
   /// Chat persistence client
-  ChatPersistenceClient get chatPersistenceClient => _chatPersistenceClient;
+  ChatPersistenceClient? get chatPersistenceClient => _chatPersistenceClient;
 
-  ChatPersistenceClient _chatPersistenceClient;
+  ChatPersistenceClient? _chatPersistenceClient;
 
   /// Attachment uploader
-  AttachmentFileUploader attachmentFileUploader;
+  AttachmentFileUploader? attachmentFileUploader;
 
   /// Whether the chat persistence is available or not
   bool get persistenceEnabled => _chatPersistenceClient != null;
 
-  RetryPolicy _retryPolicy;
+  RetryPolicy? _retryPolicy;
 
   bool _synced = false;
 
   /// The retry policy options getter
-  RetryPolicy get retryPolicy => _retryPolicy;
+  RetryPolicy? get retryPolicy => _retryPolicy;
 
   /// This client state
-  ClientState state;
+  late ClientState state;
 
   /// By default the Chat client will write all messages with level Warn or
   /// Error to stdout.
@@ -169,7 +170,7 @@ class StreamChatClient {
   /// final client = StreamChatClient("stream-chat-api-key",
   /// logHandlerFunction: myLogHandlerFunction);
   ///```
-  LogHandlerFunction logHandlerFunction;
+  late LogHandlerFunction logHandlerFunction;
 
   /// Your project Stream Chat api key.
   /// Find your API keys here https://getstream.io/dashboard/
@@ -184,7 +185,7 @@ class StreamChatClient {
   /// The token will be the return value of the function.
   /// It's used by the client to refresh the token once expired or to connect
   /// the user without a predefined token using [connectUserWithProvider].
-  final TokenProvider tokenProvider;
+  final TokenProvider? tokenProvider;
 
   /// [Dio] httpClient
   /// It's be chosen because it's easy to use and supports interesting features
@@ -195,8 +196,8 @@ class StreamChatClient {
 
   static const _defaultBaseURL = 'chat-us-east-1.stream-io-api.com';
   static const _tokenExpiredErrorCode = 40;
-  StreamSubscription<ConnectionStatus> _connectionStatusSubscription;
-  Future<void> Function(ConnectionStatus) _connectionStatusHandler;
+  StreamSubscription<ConnectionStatus>? _connectionStatusSubscription;
+  Future<void> Function(ConnectionStatus)? _connectionStatusHandler;
 
   final BehaviorSubject<Event> _controller = BehaviorSubject<Event>();
 
@@ -211,7 +212,7 @@ class StreamChatClient {
       _wsConnectionStatusController.add(status);
 
   /// The current status value of the websocket connection
-  ConnectionStatus get wsConnectionStatus =>
+  ConnectionStatus? get wsConnectionStatus =>
       _wsConnectionStatusController.value;
 
   /// This notifies the connection status of the websocket connection.
@@ -220,19 +221,19 @@ class StreamChatClient {
       _wsConnectionStatusController.stream;
 
   /// The current user token
-  String token;
+  String? token;
 
   /// The id of the current websocket connection
-  String get connectionId => _connectionId;
+  String? get connectionId => _connectionId;
 
   bool _anonymous = false;
-  String _connectionId;
-  WebSocket _ws;
+  String? _connectionId;
+  late WebSocket _ws;
 
   bool get _hasConnectionId => _connectionId != null;
 
   void _setupDio(
-    Dio httpClient,
+    Dio? httpClient,
     Duration receiveTimeout,
     Duration connectTimeout,
   ) {
@@ -267,9 +268,8 @@ class StreamChatClient {
               var stringData = options.data.toString();
 
               if (options.data is FormData) {
-                final multiPart = (options.data as FormData).files[0]?.value;
-                stringData =
-                    '${multiPart?.filename} - ${multiPart?.contentType}';
+                final multiPart = (options.data as FormData).files[0].value;
+                stringData = '${multiPart.filename} - ${multiPart.contentType}';
               }
 
               logger.info('''
@@ -301,11 +301,11 @@ class StreamChatClient {
 
       if (tokenProvider != null) {
         httpClient.lock();
-        final userId = state.user.id;
+        final userId = state.user!.id;
 
         await _disconnect();
 
-        final newToken = await tokenProvider(userId);
+        final newToken = await tokenProvider!(userId);
         await Future.delayed(const Duration(seconds: 4));
         token = newToken;
 
@@ -341,13 +341,11 @@ class StreamChatClient {
               ),
             ),
           );
-        } catch (err) {
+        } on DioError {
           handler.reject(err);
         }
       }
     }
-
-    return err;
   }
 
   LogHandlerFunction _getDefaultLogHandler() {
@@ -373,14 +371,14 @@ class StreamChatClient {
   ) =>
       Logger.detached(name)
         ..level = logLevel
-        ..onRecord.listen(logHandlerFunction ?? _getDefaultLogHandler());
+        ..onRecord.listen(logHandlerFunction);
 
-  void _setupLogger() {
+  void _setupLogger(LogHandlerFunction? logHandlerFunction) {
     logger.level = logLevel;
 
-    logHandlerFunction ??= _getDefaultLogHandler();
+    this.logHandlerFunction = logHandlerFunction ?? _getDefaultLogHandler();
 
-    logger.onRecord.listen(logHandlerFunction);
+    logger.onRecord.listen(this.logHandlerFunction);
 
     logger.info('logger setup');
   }
@@ -395,7 +393,7 @@ class StreamChatClient {
     await _wsConnectionStatusController.close();
   }
 
-  Map<String, String> get _httpHeaders => {
+  Map<String, String?> get _httpHeaders => {
         'Authorization': token,
         'stream-auth-type': _authType,
         'X-Stream-Client': _userAgent,
@@ -405,12 +403,12 @@ class StreamChatClient {
   /// Set the current user, this triggers a connection to the API.
   /// It returns a [Future] that resolves when the connection is setup.
   @Deprecated('Use `connectUser` instead. Will be removed in Future releases')
-  Future<Event> setUser(User user, String token) => connectUser(user, token);
+  Future<Event?> setUser(User user, String token) => connectUser(user, token);
 
   /// Connects the current user, this triggers a connection to the API.
   /// It returns a [Future] that resolves when the connection is setup.
-  Future<Event> connectUser(User user, String token) async {
-    if (_connectCompleter != null && !_connectCompleter.isCompleted) {
+  Future<Event?> connectUser(User? user, String? token) async {
+    if (_connectCompleter != null && !_connectCompleter!.isCompleted) {
       logger.warning('Already connecting');
       throw Exception('Already connecting');
     }
@@ -418,15 +416,23 @@ class StreamChatClient {
     _connectCompleter = Completer();
 
     logger.info('connect user');
+
+    if (user == null) {
+      final e = Error();
+      _connectCompleter!
+          .completeError(e, StackTrace.fromString('No user provided.'));
+      throw e;
+    }
+
     state.user = OwnUser.fromJson(user.toJson());
     this.token = token;
     _anonymous = false;
 
     return connect().then((event) {
-      _connectCompleter.complete(event);
+      _connectCompleter!.complete(event);
       return event;
     }).catchError((e, s) {
-      _connectCompleter.completeError(e, s);
+      _connectCompleter!.completeError(e, s);
       throw e;
     });
   }
@@ -436,28 +442,29 @@ class StreamChatClient {
   @Deprecated(
     'Use `connectUserWithProvider` instead. Will be removed in Future releases',
   )
-  Future<Event> setUserWithProvider(User user) => connectUserWithProvider(user);
+  Future<Event?> setUserWithProvider(User user) =>
+      connectUserWithProvider(user);
 
   /// Connects the current user using the [tokenProvider] to fetch the token.
   /// It returns a [Future] that resolves when the connection is setup.
-  Future<Event> connectUserWithProvider(User user) async {
+  Future<Event?> connectUserWithProvider(User user) async {
     if (tokenProvider == null) {
       throw Exception('''
       TokenProvider must be provided in the constructor in order to use `connectUserWithProvider` method.
       Use `connectUser` providing a token.
       ''');
     }
-    final token = await tokenProvider(user.id);
+    final token = await tokenProvider!(user.id);
     return connectUser(user, token);
   }
 
   /// Stream of [Event] coming from websocket connection
   /// Pass an eventType as parameter in order to filter just a type of event
   Stream<Event> on([
-    String eventType,
-    String eventType2,
-    String eventType3,
-    String eventType4,
+    String? eventType,
+    String? eventType2,
+    String? eventType3,
+    String? eventType4,
   ]) =>
       stream.where((event) =>
           eventType == null ||
@@ -475,9 +482,10 @@ class StreamChatClient {
     }
 
     if (!event.isLocal) {
-      if (_synced && event.createdAt != null) {
+      final createdAt = event.createdAt;
+      if (_synced && createdAt != null) {
         await _chatPersistenceClient?.updateConnectionInfo(event);
-        await _chatPersistenceClient?.updateLastSyncAt(event.createdAt);
+        await _chatPersistenceClient?.updateLastSyncAt(createdAt);
       }
     }
 
@@ -491,10 +499,10 @@ class StreamChatClient {
     _controller.add(event);
   }
 
-  Completer<Event> _connectCompleter;
+  Completer<Event>? _connectCompleter;
 
   /// Connect the client websocket
-  Future<Event> connect() async {
+  Future<Event?> connect() async {
     logger.info('connecting');
     if (wsConnectionStatus == ConnectionStatus.connecting) {
       logger.warning('Already connecting');
@@ -510,20 +518,20 @@ class StreamChatClient {
 
     if (_originalChatPersistenceClient != null) {
       _chatPersistenceClient = _originalChatPersistenceClient;
-      await _chatPersistenceClient.connect(state.user.id);
+      await _chatPersistenceClient!.connect(state.user!.id);
     }
 
     _ws = WebSocket(
       baseUrl: baseURL,
-      user: state.user,
+      user: state.user!,
       connectParams: {
         'api_key': apiKey,
-        'authorization': token,
+        'authorization': token!,
         'stream-auth-type': _authType,
         'X-Stream-Client': _userAgent,
       },
       connectPayload: {
-        'user_id': state.user.id,
+        'user_id': state.user!.id,
         'server_determines_connection_id': true,
       },
       handler: handleEvent,
@@ -540,7 +548,7 @@ class StreamChatClient {
       );
 
       if (status == ConnectionStatus.connected) {
-        handleEvent(Event(
+        handleEvent(const Event(
           type: EventType.connectionRecovered,
           online: true,
         ));
@@ -548,7 +556,7 @@ class StreamChatClient {
           // ignore: unawaited_futures
           queryChannelsOnline(filter: {
             'cid': {
-              '\$in': state.channels.keys.toList(),
+              '\$in': state.channels!.keys.toList(),
             },
           }).then(
             (_) async {
@@ -567,8 +575,10 @@ class StreamChatClient {
     var event = await _chatPersistenceClient?.getConnectionInfo();
 
     await _ws.connect().then((e) async {
-      await _chatPersistenceClient?.updateConnectionInfo(e);
-      event = e;
+      if (e != null) {
+        await _chatPersistenceClient?.updateConnectionInfo(e);
+        event = e;
+      }
       await resync();
     }).catchError((err, stacktrace) {
       logger.severe('error connecting ws', err, stacktrace);
@@ -582,7 +592,7 @@ class StreamChatClient {
   }
 
   /// Get the events missed while offline to sync the offline storage
-  Future<void> resync([List<String> cids]) async {
+  Future<void> resync([List<String>? cids]) async {
     final lastSyncAt = await _chatPersistenceClient?.getLastSyncAt();
 
     if (lastSyncAt == null) {
@@ -608,7 +618,7 @@ class StreamChatClient {
         SyncResponse.fromJson,
       );
 
-      res.events.sort((a, b) => a.createdAt.compareTo(b.createdAt));
+      res.events.sort((a, b) => a.createdAt!.compareTo(b.createdAt!));
 
       res.events.forEach((element) {
         logger
@@ -625,26 +635,26 @@ class StreamChatClient {
     }
   }
 
-  String _asMap(sort) => sort?.map((s) => s.toJson().toString())?.join('');
+  String? _asMap(sort) => sort?.map((s) => s.toJson().toString())?.join('');
 
   final _queryChannelsStreams = <String, Future<List<Channel>>>{};
 
   /// Requests channels with a given query.
   Stream<List<Channel>> queryChannels({
-    Map<String, dynamic> filter,
-    List<SortOption<ChannelModel>> sort,
-    Map<String, dynamic> options,
+    Map<String, dynamic>? filter,
+    List<SortOption<ChannelModel>>? sort,
+    Map<String, dynamic>? options,
     PaginationParams paginationParams = const PaginationParams(),
-    int messageLimit,
+    int? messageLimit,
     bool waitForConnect = true,
   }) async* {
     final hash = base64.encode(utf8.encode(
-      '$filter${_asMap(sort)}$options${paginationParams?.toJson()}'
+      '$filter${_asMap(sort)}$options${paginationParams.toJson()}'
       '$messageLimit',
     ));
 
     if (_queryChannelsStreams.containsKey(hash)) {
-      yield await _queryChannelsStreams[hash];
+      yield await _queryChannelsStreams[hash]!;
     } else {
       final channels = await queryChannelsOffline(
         filter: filter,
@@ -674,17 +684,17 @@ class StreamChatClient {
 
   /// Requests channels with a given query from the API.
   Future<List<Channel>> queryChannelsOnline({
-    @required Map<String, dynamic> filter,
-    List<SortOption<ChannelModel>> sort,
-    Map<String, dynamic> options,
-    int messageLimit,
+    required Map<String, dynamic>? filter,
+    List<SortOption<ChannelModel>>? sort,
+    Map<String, dynamic>? options,
+    int? messageLimit,
     PaginationParams paginationParams = const PaginationParams(),
     bool waitForConnect = true,
   }) async {
     if (waitForConnect) {
-      if (_connectCompleter != null && !_connectCompleter.isCompleted) {
+      if (_connectCompleter != null && !_connectCompleter!.isCompleted) {
         logger.info('awaiting connection completer');
-        await _connectCompleter.future;
+        await _connectCompleter!.future;
       }
       if (wsConnectionStatus != ConnectionStatus.connected) {
         throw Exception(
@@ -716,9 +726,7 @@ class StreamChatClient {
       payload.addAll(options);
     }
 
-    if (paginationParams != null) {
-      payload.addAll(paginationParams.toJson());
-    }
+    payload.addAll(paginationParams.toJson());
 
     final response = await get(
       '/channels',
@@ -732,7 +740,7 @@ class StreamChatClient {
       QueryChannelsResponse.fromJson,
     );
 
-    if ((res.channels ?? []).isEmpty && (paginationParams?.offset ?? 0) == 0) {
+    if (res.channels.isEmpty && paginationParams.offset == 0) {
       logger.warning(
         '''
         We could not find any channel for this query.
@@ -751,15 +759,14 @@ class StreamChatClient {
 
     state._updateUsers(users);
 
-    logger.info('Got ${res.channels?.length} channels from api');
+    logger.info('Got ${res.channels.length} channels from api');
 
     final updateData = _mapChannelStateToChannel(channels);
 
     await _chatPersistenceClient?.updateChannelQueries(
-      filter,
-      channels.map((c) => c.channel.cid).toList(),
-      clearQueryCache:
-          paginationParams?.offset == null || paginationParams.offset == 0,
+      filter ?? {},
+      channels.map((c) => c.channel!.cid).toList(),
+      clearQueryCache: paginationParams.offset == 0,
     );
 
     state.channels = updateData.key;
@@ -768,36 +775,34 @@ class StreamChatClient {
 
   /// Requests channels with a given query from the Persistence client.
   Future<List<Channel>> queryChannelsOffline({
-    @required Map<String, dynamic> filter,
-    @required List<SortOption<ChannelModel>> sort,
+    required Map<String, dynamic>? filter,
+    required List<SortOption<ChannelModel>>? sort,
     PaginationParams paginationParams = const PaginationParams(),
   }) async {
-    final offlineChannels = await _chatPersistenceClient?.getChannelStates(
+    final offlineChannels = (await _chatPersistenceClient?.getChannelStates(
       filter: filter,
       sort: sort,
       paginationParams: paginationParams,
-    );
+    ))!;
     final updatedData = _mapChannelStateToChannel(offlineChannels);
     state.channels = updatedData.key;
     return updatedData.value;
   }
 
-  MapEntry<Map<String, Channel>, List<Channel>> _mapChannelStateToChannel(
+  MapEntry<Map<String?, Channel>, List<Channel>> _mapChannelStateToChannel(
     List<ChannelState> channelStates,
   ) {
     final channels = {...state.channels ?? {}};
     final newChannels = <Channel>[];
-    if (channelStates != null) {
-      for (final channelState in channelStates) {
-        final channel = channels[channelState.channel.cid];
-        if (channel != null) {
-          channel.state?.updateChannelState(channelState);
-          newChannels.add(channel);
-        } else {
-          final newChannel = Channel.fromState(this, channelState);
-          channels[newChannel.cid] = newChannel;
-          newChannels.add(newChannel);
-        }
+    for (final channelState in channelStates) {
+      final channel = channels[channelState.channel!.cid];
+      if (channel != null) {
+        channel.state!.updateChannelState(channelState);
+        newChannels.add(channel);
+      } else {
+        final newChannel = Channel.fromState(this, channelState);
+        channels[newChannel.cid] = newChannel;
+        newChannels.add(newChannel);
       }
     }
     return MapEntry(channels, newChannels);
@@ -817,7 +822,7 @@ class StreamChatClient {
   /// Handy method to make http GET request with error parsing.
   Future<Response<String>> get(
     String path, {
-    Map<String, dynamic> queryParameters,
+    Map<String, dynamic>? queryParameters,
   }) async {
     try {
       final response = await httpClient.get<String>(
@@ -835,8 +840,8 @@ class StreamChatClient {
   Future<Response<String>> post(
     String path, {
     dynamic data,
-    ProgressCallback onSendProgress,
-    CancelToken cancelToken,
+    ProgressCallback? onSendProgress,
+    CancelToken? cancelToken,
   }) async {
     try {
       final response = await httpClient.post<String>(
@@ -855,8 +860,8 @@ class StreamChatClient {
   /// Handy method to make http DELETE request with error parsing.
   Future<Response<String>> delete(
     String path, {
-    Map<String, dynamic> queryParameters,
-    CancelToken cancelToken,
+    Map<String, dynamic>? queryParameters,
+    CancelToken? cancelToken,
   }) async {
     try {
       final response = await httpClient.delete<String>(
@@ -874,7 +879,7 @@ class StreamChatClient {
   /// Handy method to make http PATCH request with error parsing.
   Future<Response<String>> patch(
     String path, {
-    Map<String, dynamic> queryParameters,
+    Map<String, dynamic>? queryParameters,
     dynamic data,
   }) async {
     try {
@@ -893,7 +898,7 @@ class StreamChatClient {
   /// Handy method to make http PUT request with error parsing.
   Future<Response<String>> put(
     String path, {
-    Map<String, dynamic> queryParameters,
+    Map<String, dynamic>? queryParameters,
     dynamic data,
   }) async {
     try {
@@ -910,12 +915,10 @@ class StreamChatClient {
   }
 
   /// Used to log errors and stacktrace in case of bad json deserialization
-  T decode<T>(String j, DecoderFunction<T> decoderFunction) {
+  T decode<T>(String? j, DecoderFunction<T> decoderFunction) {
     try {
-      if (j == null) {
-        return null;
-      }
-      return decoderFunction(json.decode(j));
+      final data = j ?? '{}';
+      return decoderFunction(json.decode(data));
     } catch (error, stacktrace) {
       logger.severe('Error decoding response', error, stacktrace);
       rethrow;
@@ -927,7 +930,7 @@ class StreamChatClient {
   String get _userAgent => 'stream-chat-dart-client-${CurrentPlatform.name}-'
       '${PACKAGE_VERSION.split('+')[0]}';
 
-  Map<String, String> get _commonQueryParams => {
+  Map<String, String?> get _commonQueryParams => {
         'user_id': state.user?.id,
         'api_key': apiKey,
         'connection_id': _connectionId,
@@ -937,13 +940,13 @@ class StreamChatClient {
   /// the API. It returns a [Future] that resolves when the connection is setup.
   @Deprecated(
       'Use `connectAnonymousUser` instead. Will be removed in Future releases')
-  Future<Event> setAnonymousUser() => connectAnonymousUser();
+  Future<Event?> setAnonymousUser() => connectAnonymousUser();
 
   /// Connects the current user with an anonymous id, this triggers a connection
   /// to the API. It returns a [Future] that resolves when the connection is
   /// setup.
-  Future<Event> connectAnonymousUser() async {
-    if (_connectCompleter != null && !_connectCompleter.isCompleted) {
+  Future<Event?> connectAnonymousUser() async {
+    if (_connectCompleter != null && !_connectCompleter!.isCompleted) {
       logger.warning('Already connecting');
       throw Exception('Already connecting');
     }
@@ -955,10 +958,10 @@ class StreamChatClient {
     state.user = OwnUser(id: uuid.v4());
 
     return connect().then((event) {
-      _connectCompleter.complete(event);
+      _connectCompleter!.complete(event);
       return event;
     }).catchError((e, s) {
-      _connectCompleter.completeError(e, s);
+      _connectCompleter!.completeError(e, s);
       throw e;
     });
   }
@@ -967,16 +970,17 @@ class StreamChatClient {
   /// It returns a [Future] that resolves when the connection is setup.
   @Deprecated(
       'Use `connectGuestUser` instead. Will be removed in Future releases')
-  Future<Event> setGuestUser(User user) => connectGuestUser(user);
+  Future<Event?> setGuestUser(User user) => connectGuestUser(user);
 
   /// Connects the current user as guest, this triggers a connection to the API.
   /// It returns a [Future] that resolves when the connection is setup.
-  Future<Event> connectGuestUser(User user) async {
+  Future<Event?> connectGuestUser(User user) async {
     _anonymous = true;
     final response = await post('/guest', data: {'user': user.toJson()})
         .then((res) => decode<ConnectGuestUserResponse>(
             res.data, ConnectGuestUserResponse.fromJson))
         .whenComplete(() => _anonymous = false);
+
     return connectUser(
       response.user,
       response.accessToken,
@@ -1009,16 +1013,16 @@ class StreamChatClient {
   Future<void> _disconnect() async {
     logger.info('Client disconnecting');
 
-    await _ws?.disconnect();
+    await _ws.disconnect();
     await _connectionStatusSubscription?.cancel();
   }
 
   /// Requests users with a given query.
   Future<QueryUsersResponse> queryUsers({
-    Map<String, dynamic> filter,
-    List<SortOption> sort,
-    Map<String, dynamic> options,
-    PaginationParams pagination,
+    Map<String, dynamic>? filter,
+    List<SortOption>? sort,
+    Map<String, dynamic>? options,
+    PaginationParams? pagination,
   }) async {
     final defaultOptions = {
       'presence': _hasConnectionId,
@@ -1049,7 +1053,7 @@ class StreamChatClient {
       QueryUsersResponse.fromJson,
     );
 
-    state?._updateUsers(response.users);
+    state._updateUsers(response.users);
 
     return response;
   }
@@ -1057,13 +1061,13 @@ class StreamChatClient {
   /// A message search.
   Future<SearchMessagesResponse> search(
     Map<String, dynamic> filters, {
-    String query,
-    List<SortOption> sort,
-    PaginationParams paginationParams,
-    Map<String, dynamic> messageFilters,
+    String? query,
+    List<SortOption>? sort,
+    PaginationParams? paginationParams,
+    Map<String, dynamic>? messageFilters,
   }) async {
     assert(() {
-      if (filters == null || filters.isEmpty) {
+      if (filters.isEmpty) {
         throw ArgumentError('`filters` cannot be set as null or empty');
       }
       if (query == null && messageFilters == null) {
@@ -1098,10 +1102,10 @@ class StreamChatClient {
     AttachmentFile file,
     String channelId,
     String channelType, {
-    ProgressCallback onSendProgress,
-    CancelToken cancelToken,
+    ProgressCallback? onSendProgress,
+    CancelToken? cancelToken,
   }) =>
-      attachmentFileUploader.sendFile(
+      attachmentFileUploader!.sendFile(
         file,
         channelId,
         channelType,
@@ -1114,10 +1118,10 @@ class StreamChatClient {
     AttachmentFile image,
     String channelId,
     String channelType, {
-    ProgressCallback onSendProgress,
-    CancelToken cancelToken,
+    ProgressCallback? onSendProgress,
+    CancelToken? cancelToken,
   }) =>
-      attachmentFileUploader.sendImage(
+      attachmentFileUploader!.sendImage(
         image,
         channelId,
         channelType,
@@ -1130,9 +1134,9 @@ class StreamChatClient {
     String url,
     String channelId,
     String channelType, {
-    CancelToken cancelToken,
+    CancelToken? cancelToken,
   }) =>
-      attachmentFileUploader.deleteFile(
+      attachmentFileUploader!.deleteFile(
         url,
         channelId,
         channelType,
@@ -1144,9 +1148,9 @@ class StreamChatClient {
     String url,
     String channelId,
     String channelType, {
-    CancelToken cancelToken,
+    CancelToken? cancelToken,
   }) =>
-      attachmentFileUploader.deleteImage(
+      attachmentFileUploader!.deleteImage(
         url,
         channelId,
         channelType,
@@ -1188,13 +1192,13 @@ class StreamChatClient {
   /// Returns a channel client with the given type, id and custom data.
   Channel channel(
     String type, {
-    String id,
-    Map<String, dynamic> extraData,
+    String? id,
+    Map<String, dynamic>? extraData,
   }) {
-    if (type != null &&
-        id != null &&
-        state.channels?.containsKey('$type:$id') == true) {
-      return state.channels['$type:$id'];
+    if (id != null && state.channels?.containsKey('$type:$id') == true) {
+      if (state.channels!['$type:$id'] != null) {
+        return state.channels!['$type:$id'] as Channel;
+      }
     }
 
     return Channel(this, type, id, extraData);
@@ -1323,7 +1327,10 @@ class StreamChatClient {
 
   /// Sends the message to the given channel
   Future<SendMessageResponse> sendMessage(
-      Message message, String channelId, String channelType) async {
+    Message message,
+    String channelId,
+    String channelType,
+  ) async {
     final response = await post(
       '/channels/$channelType/$channelId/message',
       data: {'message': message.toJson()},
@@ -1359,14 +1366,13 @@ class StreamChatClient {
   ) {
     assert(() {
       if (timeoutOrExpirationDate is! DateTime &&
-          timeoutOrExpirationDate is! num &&
-          timeoutOrExpirationDate != null) {
+          timeoutOrExpirationDate is! num) {
         throw ArgumentError('Invalid timeout or Expiration date');
       }
       return true;
     }(), 'Check whether time out is valid');
 
-    DateTime pinExpires;
+    DateTime? pinExpires;
     if (timeoutOrExpirationDate is DateTime) {
       pinExpires = timeoutOrExpirationDate.toUtc();
     } else if (timeoutOrExpirationDate is num) {
@@ -1395,12 +1401,12 @@ class ClientState {
           .map((e) => e.me)
           .listen((user) {
         _userController.add(user);
-        if (user.totalUnreadCount != null) {
-          _totalUnreadCountController.add(user.totalUnreadCount);
+        if (user?.totalUnreadCount != null) {
+          _totalUnreadCountController.add(user?.totalUnreadCount);
         }
 
-        if (user.unreadChannels != null) {
-          _unreadChannelsController.add(user.unreadChannels);
+        if (user?.unreadChannels != null) {
+          _unreadChannelsController.add(user?.unreadChannels);
         }
       }),
       _client
@@ -1425,23 +1431,27 @@ class ClientState {
   final _subscriptions = <StreamSubscription>[];
 
   /// Used internally for optimistic update of unread count
-  set totalUnreadCount(int unreadCount) {
-    _totalUnreadCountController?.add(unreadCount ?? 0);
+  set totalUnreadCount(int? unreadCount) {
+    _totalUnreadCountController.add(unreadCount ?? 0);
   }
 
   void _listenChannelHidden() {
     _subscriptions.add(_client.on(EventType.channelHidden).listen((event) {
-      _client.chatPersistenceClient?.deleteChannels([event.cid]);
+      final cid = event.cid;
+
+      if (cid != null) {
+        _client.chatPersistenceClient?.deleteChannels([cid]);
+      }
       if (channels != null) {
-        channels = channels..removeWhere((cid, ch) => cid == event.cid);
+        channels = channels?..removeWhere((cid, ch) => cid == event.cid);
       }
     }));
   }
 
   void _listenUserUpdated() {
     _subscriptions.add(_client.on(EventType.userUpdated).listen((event) {
-      if (event.user.id == user.id) {
-        user = OwnUser.fromJson(event.user.toJson());
+      if (event.user!.id == user!.id) {
+        user = OwnUser.fromJson(event.user!.toJson());
       }
       _updateUser(event.user);
     }));
@@ -1455,10 +1465,10 @@ class ClientState {
       EventType.notificationChannelDeleted,
     )
         .listen((Event event) async {
-      final eventChannel = event.channel;
+      final eventChannel = event.channel!;
       await _client.chatPersistenceClient?.deleteChannels([eventChannel.cid]);
       if (channels != null) {
-        channels = channels..remove(eventChannel.cid);
+        channels = channels?..remove(eventChannel.cid);
       }
     }));
   }
@@ -1466,61 +1476,63 @@ class ClientState {
   final StreamChatClient _client;
 
   /// Update user information
-  set user(OwnUser user) {
+  set user(OwnUser? user) {
     _userController.add(user);
   }
 
-  void _updateUsers(List<User> userList) {
+  void _updateUsers(List<User?> userList) {
     final newUsers = {
-      ...users ?? {},
-      for (var user in userList) user.id: user,
+      ...users,
+      for (var user in userList) user!.id: user,
     };
     _usersController.add(newUsers);
   }
 
-  void _updateUser(User user) => _updateUsers([user]);
+  void _updateUser(User? user) => _updateUsers([user]);
 
   /// The current user
-  OwnUser get user => _userController.value;
+  OwnUser? get user => _userController.value;
 
   /// The current user as a stream
-  Stream<OwnUser> get userStream => _userController.stream;
+  Stream<OwnUser?> get userStream => _userController.stream;
 
   /// The current user
-  Map<String, User> get users => _usersController.value;
+  Map<String?, User?> get users =>
+      _usersController.value as Map<String?, User?>;
 
   /// The current user as a stream
-  Stream<Map<String, User>> get usersStream => _usersController.stream;
+  Stream<Map<String?, User?>> get usersStream => _usersController.stream;
 
   /// The current unread channels count
-  int get unreadChannels => _unreadChannelsController.value;
+  int? get unreadChannels => _unreadChannelsController.value;
 
   /// The current unread channels count as a stream
-  Stream<int> get unreadChannelsStream => _unreadChannelsController.stream;
+  Stream<int?> get unreadChannelsStream => _unreadChannelsController.stream;
 
   /// The current total unread messages count
-  int get totalUnreadCount => _totalUnreadCountController.value;
+  int? get totalUnreadCount => _totalUnreadCountController.value;
 
   /// The current total unread messages count as a stream
-  Stream<int> get totalUnreadCountStream => _totalUnreadCountController.stream;
+  Stream<int?> get totalUnreadCountStream => _totalUnreadCountController.stream;
 
   /// The current list of channels in memory as a stream
-  Stream<Map<String, Channel>> get channelsStream => _channelsController.stream;
+  Stream<Map<String?, Channel>?> get channelsStream =>
+      _channelsController.stream;
 
   /// The current list of channels in memory
-  Map<String, Channel> get channels => _channelsController.value;
+  Map<String?, Channel>? get channels => _channelsController.value;
 
-  set channels(Map<String, Channel> v) {
+  set channels(Map<String?, Channel>? v) {
     _channelsController.add(v);
   }
 
-  final BehaviorSubject<Map<String, Channel>> _channelsController =
+  final BehaviorSubject<Map<String?, Channel>?> _channelsController =
       BehaviorSubject.seeded({});
-  final BehaviorSubject<OwnUser> _userController = BehaviorSubject();
-  final BehaviorSubject<Map<String, User>> _usersController =
+  final BehaviorSubject<OwnUser?> _userController = BehaviorSubject();
+  final BehaviorSubject<Map<String?, User?>> _usersController =
       BehaviorSubject.seeded({});
-  final BehaviorSubject<int> _unreadChannelsController = BehaviorSubject();
-  final BehaviorSubject<int> _totalUnreadCountController = BehaviorSubject();
+  final BehaviorSubject<int?> _unreadChannelsController = BehaviorSubject();
+  final BehaviorSubject<int?> _totalUnreadCountController = BehaviorSubject();
 
   /// Call this method to dispose this object
   void dispose() {
@@ -1528,7 +1540,7 @@ class ClientState {
     _userController.close();
     _unreadChannelsController.close();
     _totalUnreadCountController.close();
-    channels.values.forEach((c) => c.dispose());
+    channels!.values.forEach((c) => c.dispose());
     _channelsController.close();
   }
 }
diff --git a/packages/stream_chat/lib/src/db/chat_persistence_client.dart b/packages/stream_chat/lib/src/db/chat_persistence_client.dart
index d15772df..c0f85f94 100644
--- a/packages/stream_chat/lib/src/db/chat_persistence_client.dart
+++ b/packages/stream_chat/lib/src/db/chat_persistence_client.dart
@@ -20,7 +20,7 @@ abstract class ChatPersistenceClient {
   /// Get stored replies by messageId
   Future<List<Message>> getReplies(
     String parentId, {
-    PaginationParams options,
+    PaginationParams? options,
   });
 
   /// Get stored connection event
@@ -53,20 +53,20 @@ abstract class ChatPersistenceClient {
   /// for filtering out messages
   Future<List<Message>> getMessagesByCid(
     String cid, {
-    PaginationParams messagePagination,
+    PaginationParams? messagePagination,
   });
 
   /// Get stored pinned [Message]s by providing channel [cid]
   Future<List<Message>> getPinnedMessagesByCid(
     String cid, {
-    PaginationParams messagePagination,
+    PaginationParams? messagePagination,
   });
 
   /// Get [ChannelState] data by providing channel [cid]
   Future<ChannelState> getChannelStateByCid(
     String cid, {
-    PaginationParams messagePagination,
-    PaginationParams pinnedMessagePagination,
+    PaginationParams? messagePagination,
+    PaginationParams? pinnedMessagePagination,
   }) async {
     final data = await Future.wait([
       getMembersByCid(cid),
@@ -76,11 +76,11 @@ abstract class ChatPersistenceClient {
       getPinnedMessagesByCid(cid, messagePagination: pinnedMessagePagination),
     ]);
     return ChannelState(
-      members: data[0],
-      read: data[1],
-      channel: data[2],
-      messages: data[3],
-      pinnedMessages: data[4],
+      members: data[0] as List<Member>,
+      read: data[1] as List<Read>,
+      channel: data[2] as ChannelModel,
+      messages: data[3] as List<Message>,
+      pinnedMessages: data[4] as List<Message>,
     );
   }
 
@@ -89,9 +89,9 @@ abstract class ChatPersistenceClient {
   /// Optionally, pass [filter], [sort], [paginationParams]
   /// for filtering out states.
   Future<List<ChannelState>> getChannelStates({
-    Map<String, dynamic> filter,
-    List<SortOption<ChannelModel>> sort = const [],
-    PaginationParams paginationParams,
+    Map<String, dynamic>? filter,
+    List<SortOption<ChannelModel>>? sort = const [],
+    PaginationParams? paginationParams,
   });
 
   /// Update list of channel queries.
@@ -180,8 +180,11 @@ abstract class ChatPersistenceClient {
         .map((m) => m.id)
         .toList(growable: false));
 
+    final cleanedChannelStates =
+        channelStates.where((it) => it.channel != null);
+
     final deleteMembers = deleteMembersByCids(
-      channelStates.map((it) => it.channel.cid).toList(growable: false),
+      cleanedChannelStates.map((it) => it.channel!.cid).toList(growable: false),
     );
 
     await Future.wait([
@@ -189,58 +192,57 @@ abstract class ChatPersistenceClient {
       deleteMembers,
     ]);
 
-    final channels =
-        channelStates.map((it) => it.channel).where((it) => it != null);
+    final channels = cleanedChannelStates
+        .map((it) => it.channel)
+        .where((it) => it != null) as Iterable<ChannelModel>;
 
-    final reactions = channelStates
-        .expand((it) => it.messages)
-        .expand((it) => [
+    final reactions =
+        cleanedChannelStates.expand((it) => it.messages).expand((it) => [
               if (it.ownReactions != null)
-                ...it.ownReactions.where((r) => r.userId != null),
+                ...it.ownReactions!.where((r) => r.userId != null),
               if (it.latestReactions != null)
-                ...it.latestReactions.where((r) => r.userId != null)
-            ])
-        .where((it) => it != null);
+                ...it.latestReactions!.where((r) => r.userId != null),
+            ]);
 
-    final users = channelStates
+    final users = cleanedChannelStates
         .map((cs) => [
               cs.channel?.createdBy,
               ...cs.messages
-                  ?.map((m) => [
+                  .map((m) => [
                         m.user,
                         if (m.latestReactions != null)
-                          ...m.latestReactions.map((r) => r.user),
+                          ...m.latestReactions!.map((r) => r.user),
                         if (m.ownReactions != null)
-                          ...m.ownReactions.map((r) => r.user),
+                          ...m.ownReactions!.map((r) => r.user),
                       ])
-                  ?.expand((v) => v),
-              if (cs.read != null) ...cs.read.map((r) => r.user),
-              if (cs.members != null) ...cs.members.map((m) => m.user),
+                  .expand((v) => v),
+              ...cs.read.map((r) => r.user),
+              ...cs.members.map((m) => m.user),
             ])
         .expand((it) => it)
-        .where((it) => it != null);
+        .where((it) => it != null) as Iterable<User>;
 
-    final updateMessagesFuture = channelStates.map((it) {
-      final cid = it.channel.cid;
-      final messages = it.messages.where((it) => it != null);
+    final updateMessagesFuture = cleanedChannelStates.map((it) {
+      final cid = it.channel!.cid;
+      final messages = it.messages;
       return updateMessages(cid, messages.toList(growable: false));
     }).toList(growable: false);
 
-    final updatePinnedMessagesFuture = channelStates.map((it) {
-      final cid = it.channel.cid;
-      final messages = it.pinnedMessages.where((it) => it != null);
+    final updatePinnedMessagesFuture = cleanedChannelStates.map((it) {
+      final cid = it.channel!.cid;
+      final messages = it.pinnedMessages;
       return updatePinnedMessages(cid, messages.toList(growable: false));
     }).toList(growable: false);
 
-    final updateReadsFuture = channelStates.map((it) {
-      final cid = it.channel.cid;
-      final reads = it.read?.where((it) => it != null) ?? [];
+    final updateReadsFuture = cleanedChannelStates.map((it) {
+      final cid = it.channel!.cid;
+      final reads = it.read;
       return updateReads(cid, reads.toList(growable: false));
     }).toList(growable: false);
 
-    final updateMembersFuture = channelStates.map((it) {
-      final cid = it.channel.cid;
-      final members = it.members.where((it) => it != null);
+    final updateMembersFuture = cleanedChannelStates.map((it) {
+      final cid = it.channel!.cid;
+      final members = it.members;
       return updateMembers(cid, members.toList(growable: false));
     }).toList(growable: false);
 
diff --git a/packages/stream_chat/lib/src/exceptions.dart b/packages/stream_chat/lib/src/exceptions.dart
index 60dd6bdf..714bb386 100644
--- a/packages/stream_chat/lib/src/exceptions.dart
+++ b/packages/stream_chat/lib/src/exceptions.dart
@@ -4,25 +4,25 @@ import 'dart:convert';
 class ApiError extends Error {
   /// Creates a new ApiError instance using the response body and status code
   ApiError(this.body, this.status) : jsonData = _decode(body) {
-    if (jsonData != null && jsonData.containsKey('code')) {
-      _code = jsonData['code'];
+    if (jsonData != null && jsonData!.containsKey('code')) {
+      _code = jsonData!['code'];
     }
   }
 
   /// Raw body of the response
-  final String body;
+  final String? body;
 
   /// Json parsed body
-  final Map<String, dynamic> jsonData;
+  final Map<String, dynamic>? jsonData;
 
   /// Http status code of the response
-  final int status;
+  final int? status;
 
   /// Stream specific error code
-  int get code => _code;
-  int _code;
+  int? get code => _code;
+  int? _code;
 
-  static Map<String, dynamic> _decode(String body) {
+  static Map<String, dynamic>? _decode(String? body) {
     try {
       if (body == null) {
         return null;
diff --git a/packages/stream_chat/lib/src/extensions/map_extension.dart b/packages/stream_chat/lib/src/extensions/map_extension.dart
index 1a3376ad..d99ab96a 100644
--- a/packages/stream_chat/lib/src/extensions/map_extension.dart
+++ b/packages/stream_chat/lib/src/extensions/map_extension.dart
@@ -1,6 +1,6 @@
 /// Useful extension functions for [Map]
-extension MapX on Map {
+extension MapX<K, V> on Map<K, V> {
   /// Returns a new map with null keys or values removed
-  Map<String, dynamic> get nullProtected =>
-      {...this}..removeWhere((key, value) => key == null || value == null);
+  Map<K, V> get nullProtected =>
+      Map.from(this)..removeWhere((key, value) => key == null || value == null);
 }
diff --git a/packages/stream_chat/lib/src/extensions/rate_limit.dart b/packages/stream_chat/lib/src/extensions/rate_limit.dart
index c9f5934f..bf54fe5c 100644
--- a/packages/stream_chat/lib/src/extensions/rate_limit.dart
+++ b/packages/stream_chat/lib/src/extensions/rate_limit.dart
@@ -10,7 +10,7 @@ extension RateLimit on Function {
     Duration wait, {
     bool leading = false,
     bool trailing = true,
-    Duration maxWait,
+    Duration? maxWait,
   }) =>
       Debounce(
         this,
@@ -40,7 +40,7 @@ Debounce debounce(
   Duration wait, {
   bool leading = false,
   bool trailing = true,
-  Duration maxWait,
+  Duration? maxWait,
 }) =>
     Debounce(
       func,
@@ -121,13 +121,13 @@ class Debounce {
     Duration wait, {
     bool leading = false,
     bool trailing = true,
-    Duration maxWait,
+    Duration? maxWait,
   })  : _leading = leading,
         _trailing = trailing,
-        _wait = wait?.inMilliseconds ?? 0,
+        _wait = wait.inMilliseconds,
         _maxing = maxWait != null {
     if (_maxing) {
-      _maxWait = math.max(maxWait.inMilliseconds, _wait);
+      _maxWait = math.max(maxWait!.inMilliseconds, _wait);
     }
   }
 
@@ -137,15 +137,15 @@ class Debounce {
   final int _wait;
   final bool _maxing;
 
-  int _maxWait;
-  List<Object> _lastArgs;
-  Map<Symbol, Object> _lastNamedArgs;
-  Timer _timer;
-  int _lastCallTime;
-  Object _result;
-  int _lastInvokeTime = 0;
+  late int _maxWait;
+  List<Object?>? _lastArgs;
+  Map<Symbol, Object>? _lastNamedArgs;
+  Timer? _timer;
+  int? _lastCallTime;
+  Object? _result;
+  int? _lastInvokeTime = 0;
 
-  Object _invokeFunc(int time) {
+  Object? _invokeFunc(int? time) {
     final args = _lastArgs;
     final namedArgs = _lastNamedArgs;
     _lastArgs = _lastNamedArgs = null;
@@ -154,11 +154,11 @@ class Debounce {
   }
 
   Timer _startTimer(Function pendingFunc, int wait) =>
-      Timer(Duration(milliseconds: wait), pendingFunc);
+      Timer(Duration(milliseconds: wait), pendingFunc as void Function());
 
   bool _shouldInvoke(int time) {
     final timeSinceLastCall = time - (_lastCallTime ?? double.nan);
-    final timeSinceLastInvoke = time - _lastInvokeTime;
+    final timeSinceLastInvoke = time - _lastInvokeTime!;
 
     // Either this is the first call, activity has stopped and we're at the
     // trailing edge, the system time has gone backwards and we're treating
@@ -169,7 +169,7 @@ class Debounce {
         (_maxing && timeSinceLastInvoke >= _maxWait);
   }
 
-  Object _trailingEdge(int time) {
+  Object? _trailingEdge(int time) {
     _timer = null;
 
     // Only invoke if we have `lastArgs` which means `func` has been
@@ -182,8 +182,8 @@ class Debounce {
   }
 
   int _remainingWait(int time) {
-    final timeSinceLastCall = time - _lastCallTime;
-    final timeSinceLastInvoke = time - _lastInvokeTime;
+    final timeSinceLastCall = time - _lastCallTime!;
+    final timeSinceLastInvoke = time - _lastInvokeTime!;
     final timeWaiting = _wait - timeSinceLastCall;
 
     return _maxing
@@ -201,7 +201,7 @@ class Debounce {
     }
   }
 
-  Object _leadingEdge(int time) {
+  Object? _leadingEdge(int? time) {
     // Reset any `maxWait` timer.
     _lastInvokeTime = time;
     // Start the timer for the trailing edge.
@@ -218,7 +218,7 @@ class Debounce {
   }
 
   /// Immediately invokes all the remaining delayed functions.
-  Object flush() {
+  Object? flush() {
     final now = DateTime.now().millisecondsSinceEpoch;
     return _timer == null ? _result : _trailingEdge(now);
   }
@@ -228,15 +228,15 @@ class Debounce {
 
   /// Calls/invokes this class like a function.
   /// Pass [args] and [namedArgs] to be used while invoking [_func].
-  Object call(
+  Object? call(
     List<dynamic> args, {
-    Map<Symbol, dynamic> namedArgs,
+    Map<Symbol, dynamic>? namedArgs,
   }) {
     final time = DateTime.now().millisecondsSinceEpoch;
     final isInvoking = _shouldInvoke(time);
 
     _lastArgs = args;
-    _lastNamedArgs = namedArgs;
+    _lastNamedArgs = namedArgs as Map<Symbol, Object>?;
     _lastCallTime = time;
 
     if (isInvoking) {
@@ -323,13 +323,13 @@ class Throttle {
   void cancel() => _debounce.cancel();
 
   /// Immediately invokes all the remaining delayed functions.
-  Object flush() => _debounce.flush();
+  Object? flush() => _debounce.flush();
 
   /// True if there are functions remaining to get invoked.
   bool get isPending => _debounce.isPending;
 
   /// Calls/invokes this class like a function.
   /// Pass [args] and [namedArgs] to be used while invoking `func`.
-  Object call(List<dynamic> args, {Map<Symbol, dynamic> namedArgs}) =>
+  Object? call(List<dynamic> args, {Map<Symbol, dynamic>? namedArgs}) =>
       _debounce.call(args, namedArgs: namedArgs);
 }
diff --git a/packages/stream_chat/lib/src/extensions/string_extension.dart b/packages/stream_chat/lib/src/extensions/string_extension.dart
index 49949412..440e2cb6 100644
--- a/packages/stream_chat/lib/src/extensions/string_extension.dart
+++ b/packages/stream_chat/lib/src/extensions/string_extension.dart
@@ -4,12 +4,15 @@ import 'package:mime/mime.dart';
 /// Useful extension functions for [String]
 extension StringX on String {
   /// Returns the mime type from the passed file name.
-  http_parser.MediaType get mimeType {
-    if (this == null) return null;
+  http_parser.MediaType? get mimeType {
     if (toLowerCase().endsWith('heic')) {
       return http_parser.MediaType.parse('image/heic');
     } else {
-      return http_parser.MediaType.parse(lookupMimeType(this));
+      final mimeType = lookupMimeType(this);
+      if (mimeType == null) {
+        return null;
+      }
+      return http_parser.MediaType.parse(mimeType);
     }
   }
 }
diff --git a/packages/stream_chat/lib/src/models/action.dart b/packages/stream_chat/lib/src/models/action.dart
index 62d0f104..16a307e7 100644
--- a/packages/stream_chat/lib/src/models/action.dart
+++ b/packages/stream_chat/lib/src/models/action.dart
@@ -6,7 +6,13 @@ part 'action.g.dart';
 @JsonSerializable()
 class Action {
   /// Constructor used for json serialization
-  Action({this.name, this.style, this.text, this.type, this.value});
+  Action({
+    required this.name,
+    this.style = 'default',
+    required this.text,
+    required this.type,
+    this.value,
+  });
 
   /// Create a new instance from a json
   factory Action.fromJson(Map<String, dynamic> json) => _$ActionFromJson(json);
@@ -15,6 +21,7 @@ class Action {
   final String name;
 
   /// The style of the action
+  @JsonKey(defaultValue: 'default')
   final String style;
 
   /// The test of the action
@@ -24,7 +31,7 @@ class Action {
   final String type;
 
   /// The value of the action
-  final String value;
+  final String? value;
 
   /// Serialize to json
   Map<String, dynamic> toJson() => _$ActionToJson(this);
diff --git a/packages/stream_chat/lib/src/models/action.g.dart b/packages/stream_chat/lib/src/models/action.g.dart
index 3c567843..9ae999ed 100644
--- a/packages/stream_chat/lib/src/models/action.g.dart
+++ b/packages/stream_chat/lib/src/models/action.g.dart
@@ -6,13 +6,13 @@ part of 'action.dart';
 // JsonSerializableGenerator
 // **************************************************************************
 
-Action _$ActionFromJson(Map json) {
+Action _$ActionFromJson(Map<String, dynamic> json) {
   return Action(
     name: json['name'] as String,
-    style: json['style'] as String,
+    style: json['style'] as String? ?? 'default',
     text: json['text'] as String,
     type: json['type'] as String,
-    value: json['value'] as String,
+    value: json['value'] as String?,
   );
 }
 
diff --git a/packages/stream_chat/lib/src/models/attachment.dart b/packages/stream_chat/lib/src/models/attachment.dart
index 8c9406c8..fd91454a 100644
--- a/packages/stream_chat/lib/src/models/attachment.dart
+++ b/packages/stream_chat/lib/src/models/attachment.dart
@@ -14,10 +14,10 @@ part 'attachment.g.dart';
 class Attachment extends Equatable {
   /// Constructor used for json serialization
   Attachment({
-    String id,
+    String? id,
     this.type,
     this.titleLink,
-    String title,
+    String? title,
     this.thumbUrl,
     this.text,
     this.pretext,
@@ -32,17 +32,19 @@ class Attachment extends Equatable {
     this.authorLink,
     this.authorIcon,
     this.assetUrl,
-    this.actions,
+    List<Action>? actions,
     this.extraData,
     this.file,
-    UploadState uploadState,
+    UploadState? uploadState,
   })  : id = id ?? const Uuid().v4(),
         title = title ?? file?.name,
-        localUri = file?.path != null ? Uri.parse(file.path) : null,
-        uploadState = uploadState ??
-            ((assetUrl != null || imageUrl != null)
-                ? const UploadState.success()
-                : const UploadState.preparing());
+        localUri = file?.path != null ? Uri.parse(file!.path!) : null,
+        actions = actions ?? [] {
+    this.uploadState = uploadState ??
+        ((assetUrl != null || imageUrl != null)
+            ? const UploadState.success()
+            : const UploadState.preparing());
+  }
 
   /// Create a new instance from a json
   factory Attachment.fromJson(Map<String, dynamic> json) =>
@@ -56,59 +58,60 @@ class Attachment extends Equatable {
 
   ///The attachment type based on the URL resource. This can be: audio,
   ///image or video
-  final String type;
+  final String? type;
 
   ///The link to which the attachment message points to.
-  final String titleLink;
+  final String? titleLink;
 
   /// The attachment title
-  final String title;
+  final String? title;
 
   /// The URL to the attached file thumbnail. You can use this to represent the
   /// attached link.
-  final String thumbUrl;
+  final String? thumbUrl;
 
   /// The attachment text. It will be displayed in the channel next to the
   /// original message.
-  final String text;
+  final String? text;
 
   /// Optional text that appears above the attachment block
-  final String pretext;
+  final String? pretext;
 
   /// The original URL that was used to scrape this attachment.
-  final String ogScrapeUrl;
+  final String? ogScrapeUrl;
 
   /// The URL to the attached image. This is present for URL pointing to an
   /// image article (eg. Unsplash)
-  final String imageUrl;
-  final String footerIcon;
-  final String footer;
+  final String? imageUrl;
+  final String? footerIcon;
+  final String? footer;
   final dynamic fields;
-  final String fallback;
-  final String color;
+  final String? fallback;
+  final String? color;
 
   /// The name of the author.
-  final String authorName;
-  final String authorLink;
-  final String authorIcon;
+  final String? authorName;
+  final String? authorLink;
+  final String? authorIcon;
 
   /// The URL to the audio, video or image related to the URL.
-  final String assetUrl;
+  final String? assetUrl;
 
   /// Actions from a command
+  @JsonKey(defaultValue: [])
   final List<Action> actions;
 
-  final Uri localUri;
+  final Uri? localUri;
 
   /// The file present inside this attachment.
-  final AttachmentFile file;
+  final AttachmentFile? file;
 
   /// The current upload state of the attachment
-  final UploadState uploadState;
+  late final UploadState uploadState;
 
   /// Map of custom channel extraData
   @JsonKey(includeIfNull: false)
-  final Map<String, dynamic> extraData;
+  final Map<String, dynamic>? extraData;
 
   /// The attachment ID.
   ///
@@ -147,37 +150,37 @@ class Attachment extends Equatable {
   ];
 
   /// Serialize to json
-  Map<String, dynamic> toJson() => Serialization.moveFromExtraDataToRoot(
-      _$AttachmentToJson(this), topLevelFields)
-    ..removeWhere((key, value) => dbSpecificTopLevelFields.contains(key));
+  Map<String, dynamic> toJson() =>
+      Serialization.moveFromExtraDataToRoot(_$AttachmentToJson(this))
+        ..removeWhere((key, value) => dbSpecificTopLevelFields.contains(key));
 
   /// Serialize to db data
-  Map<String, dynamic> toData() => Serialization.moveFromExtraDataToRoot(
-      _$AttachmentToJson(this), topLevelFields + dbSpecificTopLevelFields);
+  Map<String, dynamic> toData() =>
+      Serialization.moveFromExtraDataToRoot(_$AttachmentToJson(this));
 
   Attachment copyWith({
-    String id,
-    String type,
-    String titleLink,
-    String title,
-    String thumbUrl,
-    String text,
-    String pretext,
-    String ogScrapeUrl,
-    String imageUrl,
-    String footerIcon,
-    String footer,
+    String? id,
+    String? type,
+    String? titleLink,
+    String? title,
+    String? thumbUrl,
+    String? text,
+    String? pretext,
+    String? ogScrapeUrl,
+    String? imageUrl,
+    String? footerIcon,
+    String? footer,
     dynamic fields,
-    String fallback,
-    String color,
-    String authorName,
-    String authorLink,
-    String authorIcon,
-    String assetUrl,
-    List<Action> actions,
-    AttachmentFile file,
-    UploadState uploadState,
-    Map<String, dynamic> extraData,
+    String? fallback,
+    String? color,
+    String? authorName,
+    String? authorLink,
+    String? authorIcon,
+    String? assetUrl,
+    List<Action>? actions,
+    AttachmentFile? file,
+    UploadState? uploadState,
+    Map<String, dynamic>? extraData,
   }) =>
       Attachment(
         id: id ?? this.id,
@@ -205,7 +208,7 @@ class Attachment extends Equatable {
       );
 
   @override
-  List<Object> get props => [
+  List<Object?> get props => [
         id,
         type,
         titleLink,
diff --git a/packages/stream_chat/lib/src/models/attachment.g.dart b/packages/stream_chat/lib/src/models/attachment.g.dart
index c45771c2..b7a7304d 100644
--- a/packages/stream_chat/lib/src/models/attachment.g.dart
+++ b/packages/stream_chat/lib/src/models/attachment.g.dart
@@ -6,46 +6,37 @@ part of 'attachment.dart';
 // JsonSerializableGenerator
 // **************************************************************************
 
-Attachment _$AttachmentFromJson(Map json) {
+Attachment _$AttachmentFromJson(Map<String, dynamic> json) {
   return Attachment(
-    id: json['id'] as String,
-    type: json['type'] as String,
-    titleLink: json['title_link'] as String,
-    title: json['title'] as String,
-    thumbUrl: json['thumb_url'] as String,
-    text: json['text'] as String,
-    pretext: json['pretext'] as String,
-    ogScrapeUrl: json['og_scrape_url'] as String,
-    imageUrl: json['image_url'] as String,
-    footerIcon: json['footer_icon'] as String,
-    footer: json['footer'] as String,
+    id: json['id'] as String?,
+    type: json['type'] as String?,
+    titleLink: json['title_link'] as String?,
+    title: json['title'] as String?,
+    thumbUrl: json['thumb_url'] as String?,
+    text: json['text'] as String?,
+    pretext: json['pretext'] as String?,
+    ogScrapeUrl: json['og_scrape_url'] as String?,
+    imageUrl: json['image_url'] as String?,
+    footerIcon: json['footer_icon'] as String?,
+    footer: json['footer'] as String?,
     fields: json['fields'],
-    fallback: json['fallback'] as String,
-    color: json['color'] as String,
-    authorName: json['author_name'] as String,
-    authorLink: json['author_link'] as String,
-    authorIcon: json['author_icon'] as String,
-    assetUrl: json['asset_url'] as String,
-    actions: (json['actions'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Action.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList(),
-    extraData: (json['extra_data'] as Map)?.map(
-      (k, e) => MapEntry(k as String, e),
-    ),
+    fallback: json['fallback'] as String?,
+    color: json['color'] as String?,
+    authorName: json['author_name'] as String?,
+    authorLink: json['author_link'] as String?,
+    authorIcon: json['author_icon'] as String?,
+    assetUrl: json['asset_url'] as String?,
+    actions: (json['actions'] as List<dynamic>?)
+            ?.map((e) => Action.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [],
+    extraData: json['extra_data'] as Map<String, dynamic>?,
     file: json['file'] == null
         ? null
-        : AttachmentFile.fromJson((json['file'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
+        : AttachmentFile.fromJson(json['file'] as Map<String, dynamic>),
     uploadState: json['upload_state'] == null
         ? null
-        : UploadState.fromJson((json['upload_state'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
+        : UploadState.fromJson(json['upload_state'] as Map<String, dynamic>),
   );
 }
 
@@ -75,10 +66,10 @@ Map<String, dynamic> _$AttachmentToJson(Attachment instance) {
   writeNotNull('author_link', instance.authorLink);
   writeNotNull('author_icon', instance.authorIcon);
   writeNotNull('asset_url', instance.assetUrl);
-  writeNotNull('actions', instance.actions?.map((e) => e?.toJson())?.toList());
+  val['actions'] = instance.actions.map((e) => e.toJson()).toList();
   writeNotNull('file', instance.file?.toJson());
-  writeNotNull('upload_state', instance.uploadState?.toJson());
+  val['upload_state'] = instance.uploadState.toJson();
   writeNotNull('extra_data', instance.extraData);
-  writeNotNull('id', instance.id);
+  val['id'] = instance.id;
   return val;
 }
diff --git a/packages/stream_chat/lib/src/models/attachment_file.dart b/packages/stream_chat/lib/src/models/attachment_file.dart
index bae7810f..d72cecbd 100644
--- a/packages/stream_chat/lib/src/models/attachment_file.dart
+++ b/packages/stream_chat/lib/src/models/attachment_file.dart
@@ -8,18 +8,21 @@ part 'attachment_file.g.dart';
 
 /// Union class to hold various [UploadState] of a attachment.
 @freezed
-abstract class UploadState with _$UploadState {
+class UploadState with _$UploadState {
   /// Preparing state of the union
   const factory UploadState.preparing() = Preparing;
 
   /// InProgress state of the union
-  const factory UploadState.inProgress({int uploaded, int total}) = InProgress;
+  const factory UploadState.inProgress({
+    required int uploaded,
+    required int total,
+  }) = InProgress;
 
   /// Success state of the union
   const factory UploadState.success() = Success;
 
   /// Failed state of the union
-  const factory UploadState.failed({@required String error}) = Failed;
+  const factory UploadState.failed({required String error}) = Failed;
 
   /// Creates a new instance from a json
   factory UploadState.fromJson(Map<String, dynamic> json) =>
@@ -27,7 +30,7 @@ abstract class UploadState with _$UploadState {
 }
 
 /// Helper extension for UploadState
-extension UploadStateX on UploadState {
+extension UploadStateX on UploadState? {
   /// Returns true if state is [Preparing]
   bool get isPreparing => this is Preparing;
 
@@ -41,9 +44,15 @@ extension UploadStateX on UploadState {
   bool get isFailed => this is Failed;
 }
 
-Uint8List _fromString(String bytes) => Uint8List.fromList(bytes.codeUnits);
+Uint8List? _fromString(String? bytes) {
+  if (bytes == null) return null;
+  return Uint8List.fromList(bytes.codeUnits);
+}
 
-String _toString(Uint8List bytes) => String.fromCharCodes(bytes);
+String? _toString(Uint8List? bytes) {
+  if (bytes == null) return null;
+  return String.fromCharCodes(bytes);
+}
 
 /// The class that contains the information about an attachment file
 @JsonSerializable()
@@ -54,7 +63,10 @@ class AttachmentFile {
     this.name,
     this.bytes,
     this.size,
-  });
+  }) : assert(
+          path != null || bytes != null,
+          'Either path or bytes should be != null',
+        );
 
   /// Create a new instance from a json
   factory AttachmentFile.fromJson(Map<String, dynamic> json) =>
@@ -65,21 +77,21 @@ class AttachmentFile {
   /// ```
   /// final File myFile = File(platformFile.path);
   /// ```
-  final String path;
+  final String? path;
 
   /// File name including its extension.
-  final String name;
+  final String? name;
 
   /// Byte data for this file. Particularly useful if you want to manipulate
   /// its data or easily upload to somewhere else.
   @JsonKey(toJson: _toString, fromJson: _fromString)
-  final Uint8List bytes;
+  final Uint8List? bytes;
 
   /// The file size in bytes.
-  final int size;
+  final int? size;
 
   /// File extension for this file.
-  String get extension => name?.split('.')?.last;
+  String? get extension => name?.split('.').last;
 
   /// Serialize to json
   Map<String, dynamic> toJson() => _$AttachmentFileToJson(this);
diff --git a/packages/stream_chat/lib/src/models/attachment_file.freezed.dart b/packages/stream_chat/lib/src/models/attachment_file.freezed.dart
index 4eea1f13..a6c5e0c6 100644
--- a/packages/stream_chat/lib/src/models/attachment_file.freezed.dart
+++ b/packages/stream_chat/lib/src/models/attachment_file.freezed.dart
@@ -1,5 +1,5 @@
 // GENERATED CODE - DO NOT MODIFY BY HAND
-// ignore_for_file: deprecated_member_use, deprecated_member_use_from_same_package, use_function_type_syntax_for_parameters, unnecessary_const, avoid_init_to_null, invalid_override_different_default_values_named, prefer_expression_function_bodies
+// ignore_for_file: unused_element, deprecated_member_use, deprecated_member_use_from_same_package, use_function_type_syntax_for_parameters, unnecessary_const, avoid_init_to_null, invalid_override_different_default_values_named, prefer_expression_function_bodies, annotate_overrides
 
 part of 'attachment_file.dart';
 
@@ -8,6 +8,10 @@ part of 'attachment_file.dart';
 // **************************************************************************
 
 T _$identity<T>(T value) => value;
+
+final _privateConstructorUsedError = UnsupportedError(
+    'It seems like you constructed your class using `MyClass._()`. This constructor is only meant to be used by freezed and you are not supposed to need it nor use it.\nPlease check the documentation here for more informations: https://github.com/rrousselGit/freezed#custom-getters-and-methods');
+
 UploadState _$UploadStateFromJson(Map<String, dynamic> json) {
   switch (json['runtimeType'] as String) {
     case 'preparing':
@@ -28,74 +32,72 @@ UploadState _$UploadStateFromJson(Map<String, dynamic> json) {
 class _$UploadStateTearOff {
   const _$UploadStateTearOff();
 
-// ignore: unused_element
   Preparing preparing() {
     return const Preparing();
   }
 
-// ignore: unused_element
-  InProgress inProgress({int uploaded, int total}) {
+  InProgress inProgress({required int uploaded, required int total}) {
     return InProgress(
       uploaded: uploaded,
       total: total,
     );
   }
 
-// ignore: unused_element
   Success success() {
     return const Success();
   }
 
-// ignore: unused_element
-  Failed failed({@required String error}) {
+  Failed failed({required String error}) {
     return Failed(
       error: error,
     );
   }
 
-// ignore: unused_element
   UploadState fromJson(Map<String, Object> json) {
     return UploadState.fromJson(json);
   }
 }
 
 /// @nodoc
-// ignore: unused_element
 const $UploadState = _$UploadStateTearOff();
 
 /// @nodoc
 mixin _$UploadState {
   @optionalTypeArgs
-  TResult when<TResult extends Object>({
-    @required TResult preparing(),
-    @required TResult inProgress(int uploaded, int total),
-    @required TResult success(),
-    @required TResult failed(String error),
-  });
+  TResult when<TResult extends Object?>({
+    required TResult Function() preparing,
+    required TResult Function(int uploaded, int total) inProgress,
+    required TResult Function() success,
+    required TResult Function(String error) failed,
+  }) =>
+      throw _privateConstructorUsedError;
   @optionalTypeArgs
-  TResult maybeWhen<TResult extends Object>({
-    TResult preparing(),
-    TResult inProgress(int uploaded, int total),
-    TResult success(),
-    TResult failed(String error),
-    @required TResult orElse(),
-  });
+  TResult maybeWhen<TResult extends Object?>({
+    TResult Function()? preparing,
+    TResult Function(int uploaded, int total)? inProgress,
+    TResult Function()? success,
+    TResult Function(String error)? failed,
+    required TResult orElse(),
+  }) =>
+      throw _privateConstructorUsedError;
   @optionalTypeArgs
-  TResult map<TResult extends Object>({
-    @required TResult preparing(Preparing value),
-    @required TResult inProgress(InProgress value),
-    @required TResult success(Success value),
-    @required TResult failed(Failed value),
-  });
+  TResult map<TResult extends Object?>({
+    required TResult Function(Preparing value) preparing,
+    required TResult Function(InProgress value) inProgress,
+    required TResult Function(Success value) success,
+    required TResult Function(Failed value) failed,
+  }) =>
+      throw _privateConstructorUsedError;
   @optionalTypeArgs
-  TResult maybeMap<TResult extends Object>({
-    TResult preparing(Preparing value),
-    TResult inProgress(InProgress value),
-    TResult success(Success value),
-    TResult failed(Failed value),
-    @required TResult orElse(),
-  });
-  Map<String, dynamic> toJson();
+  TResult maybeMap<TResult extends Object?>({
+    TResult Function(Preparing value)? preparing,
+    TResult Function(InProgress value)? inProgress,
+    TResult Function(Success value)? success,
+    TResult Function(Failed value)? failed,
+    required TResult orElse(),
+  }) =>
+      throw _privateConstructorUsedError;
+  Map<String, dynamic> toJson() => throw _privateConstructorUsedError;
 }
 
 /// @nodoc
@@ -154,29 +156,24 @@ class _$Preparing implements Preparing {
 
   @override
   @optionalTypeArgs
-  TResult when<TResult extends Object>({
-    @required TResult preparing(),
-    @required TResult inProgress(int uploaded, int total),
-    @required TResult success(),
-    @required TResult failed(String error),
+  TResult when<TResult extends Object?>({
+    required TResult Function() preparing,
+    required TResult Function(int uploaded, int total) inProgress,
+    required TResult Function() success,
+    required TResult Function(String error) failed,
   }) {
-    assert(preparing != null);
-    assert(inProgress != null);
-    assert(success != null);
-    assert(failed != null);
     return preparing();
   }
 
   @override
   @optionalTypeArgs
-  TResult maybeWhen<TResult extends Object>({
-    TResult preparing(),
-    TResult inProgress(int uploaded, int total),
-    TResult success(),
-    TResult failed(String error),
-    @required TResult orElse(),
+  TResult maybeWhen<TResult extends Object?>({
+    TResult Function()? preparing,
+    TResult Function(int uploaded, int total)? inProgress,
+    TResult Function()? success,
+    TResult Function(String error)? failed,
+    required TResult orElse(),
   }) {
-    assert(orElse != null);
     if (preparing != null) {
       return preparing();
     }
@@ -185,29 +182,24 @@ class _$Preparing implements Preparing {
 
   @override
   @optionalTypeArgs
-  TResult map<TResult extends Object>({
-    @required TResult preparing(Preparing value),
-    @required TResult inProgress(InProgress value),
-    @required TResult success(Success value),
-    @required TResult failed(Failed value),
+  TResult map<TResult extends Object?>({
+    required TResult Function(Preparing value) preparing,
+    required TResult Function(InProgress value) inProgress,
+    required TResult Function(Success value) success,
+    required TResult Function(Failed value) failed,
   }) {
-    assert(preparing != null);
-    assert(inProgress != null);
-    assert(success != null);
-    assert(failed != null);
     return preparing(this);
   }
 
   @override
   @optionalTypeArgs
-  TResult maybeMap<TResult extends Object>({
-    TResult preparing(Preparing value),
-    TResult inProgress(InProgress value),
-    TResult success(Success value),
-    TResult failed(Failed value),
-    @required TResult orElse(),
+  TResult maybeMap<TResult extends Object?>({
+    TResult Function(Preparing value)? preparing,
+    TResult Function(InProgress value)? inProgress,
+    TResult Function(Success value)? success,
+    TResult Function(Failed value)? failed,
+    required TResult orElse(),
   }) {
-    assert(orElse != null);
     if (preparing != null) {
       return preparing(this);
     }
@@ -245,12 +237,18 @@ class _$InProgressCopyWithImpl<$Res> extends _$UploadStateCopyWithImpl<$Res>
 
   @override
   $Res call({
-    Object uploaded = freezed,
-    Object total = freezed,
+    Object? uploaded = freezed,
+    Object? total = freezed,
   }) {
     return _then(InProgress(
-      uploaded: uploaded == freezed ? _value.uploaded : uploaded as int,
-      total: total == freezed ? _value.total : total as int,
+      uploaded: uploaded == freezed
+          ? _value.uploaded
+          : uploaded // ignore: cast_nullable_to_non_nullable
+              as int,
+      total: total == freezed
+          ? _value.total
+          : total // ignore: cast_nullable_to_non_nullable
+              as int,
     ));
   }
 }
@@ -259,7 +257,7 @@ class _$InProgressCopyWithImpl<$Res> extends _$UploadStateCopyWithImpl<$Res>
 
 /// @nodoc
 class _$InProgress implements InProgress {
-  const _$InProgress({this.uploaded, this.total});
+  const _$InProgress({required this.uploaded, required this.total});
 
   factory _$InProgress.fromJson(Map<String, dynamic> json) =>
       _$_$InProgressFromJson(json);
@@ -298,29 +296,24 @@ class _$InProgress implements InProgress {
 
   @override
   @optionalTypeArgs
-  TResult when<TResult extends Object>({
-    @required TResult preparing(),
-    @required TResult inProgress(int uploaded, int total),
-    @required TResult success(),
-    @required TResult failed(String error),
+  TResult when<TResult extends Object?>({
+    required TResult Function() preparing,
+    required TResult Function(int uploaded, int total) inProgress,
+    required TResult Function() success,
+    required TResult Function(String error) failed,
   }) {
-    assert(preparing != null);
-    assert(inProgress != null);
-    assert(success != null);
-    assert(failed != null);
     return inProgress(uploaded, total);
   }
 
   @override
   @optionalTypeArgs
-  TResult maybeWhen<TResult extends Object>({
-    TResult preparing(),
-    TResult inProgress(int uploaded, int total),
-    TResult success(),
-    TResult failed(String error),
-    @required TResult orElse(),
+  TResult maybeWhen<TResult extends Object?>({
+    TResult Function()? preparing,
+    TResult Function(int uploaded, int total)? inProgress,
+    TResult Function()? success,
+    TResult Function(String error)? failed,
+    required TResult orElse(),
   }) {
-    assert(orElse != null);
     if (inProgress != null) {
       return inProgress(uploaded, total);
     }
@@ -329,29 +322,24 @@ class _$InProgress implements InProgress {
 
   @override
   @optionalTypeArgs
-  TResult map<TResult extends Object>({
-    @required TResult preparing(Preparing value),
-    @required TResult inProgress(InProgress value),
-    @required TResult success(Success value),
-    @required TResult failed(Failed value),
+  TResult map<TResult extends Object?>({
+    required TResult Function(Preparing value) preparing,
+    required TResult Function(InProgress value) inProgress,
+    required TResult Function(Success value) success,
+    required TResult Function(Failed value) failed,
   }) {
-    assert(preparing != null);
-    assert(inProgress != null);
-    assert(success != null);
-    assert(failed != null);
     return inProgress(this);
   }
 
   @override
   @optionalTypeArgs
-  TResult maybeMap<TResult extends Object>({
-    TResult preparing(Preparing value),
-    TResult inProgress(InProgress value),
-    TResult success(Success value),
-    TResult failed(Failed value),
-    @required TResult orElse(),
+  TResult maybeMap<TResult extends Object?>({
+    TResult Function(Preparing value)? preparing,
+    TResult Function(InProgress value)? inProgress,
+    TResult Function(Success value)? success,
+    TResult Function(Failed value)? failed,
+    required TResult orElse(),
   }) {
-    assert(orElse != null);
     if (inProgress != null) {
       return inProgress(this);
     }
@@ -365,15 +353,17 @@ class _$InProgress implements InProgress {
 }
 
 abstract class InProgress implements UploadState {
-  const factory InProgress({int uploaded, int total}) = _$InProgress;
+  const factory InProgress({required int uploaded, required int total}) =
+      _$InProgress;
 
   factory InProgress.fromJson(Map<String, dynamic> json) =
       _$InProgress.fromJson;
 
-  int get uploaded;
-  int get total;
+  int get uploaded => throw _privateConstructorUsedError;
+  int get total => throw _privateConstructorUsedError;
   @JsonKey(ignore: true)
-  $InProgressCopyWith<InProgress> get copyWith;
+  $InProgressCopyWith<InProgress> get copyWith =>
+      throw _privateConstructorUsedError;
 }
 
 /// @nodoc
@@ -416,29 +406,24 @@ class _$Success implements Success {
 
   @override
   @optionalTypeArgs
-  TResult when<TResult extends Object>({
-    @required TResult preparing(),
-    @required TResult inProgress(int uploaded, int total),
-    @required TResult success(),
-    @required TResult failed(String error),
+  TResult when<TResult extends Object?>({
+    required TResult Function() preparing,
+    required TResult Function(int uploaded, int total) inProgress,
+    required TResult Function() success,
+    required TResult Function(String error) failed,
   }) {
-    assert(preparing != null);
-    assert(inProgress != null);
-    assert(success != null);
-    assert(failed != null);
     return success();
   }
 
   @override
   @optionalTypeArgs
-  TResult maybeWhen<TResult extends Object>({
-    TResult preparing(),
-    TResult inProgress(int uploaded, int total),
-    TResult success(),
-    TResult failed(String error),
-    @required TResult orElse(),
+  TResult maybeWhen<TResult extends Object?>({
+    TResult Function()? preparing,
+    TResult Function(int uploaded, int total)? inProgress,
+    TResult Function()? success,
+    TResult Function(String error)? failed,
+    required TResult orElse(),
   }) {
-    assert(orElse != null);
     if (success != null) {
       return success();
     }
@@ -447,29 +432,24 @@ class _$Success implements Success {
 
   @override
   @optionalTypeArgs
-  TResult map<TResult extends Object>({
-    @required TResult preparing(Preparing value),
-    @required TResult inProgress(InProgress value),
-    @required TResult success(Success value),
-    @required TResult failed(Failed value),
+  TResult map<TResult extends Object?>({
+    required TResult Function(Preparing value) preparing,
+    required TResult Function(InProgress value) inProgress,
+    required TResult Function(Success value) success,
+    required TResult Function(Failed value) failed,
   }) {
-    assert(preparing != null);
-    assert(inProgress != null);
-    assert(success != null);
-    assert(failed != null);
     return success(this);
   }
 
   @override
   @optionalTypeArgs
-  TResult maybeMap<TResult extends Object>({
-    TResult preparing(Preparing value),
-    TResult inProgress(InProgress value),
-    TResult success(Success value),
-    TResult failed(Failed value),
-    @required TResult orElse(),
+  TResult maybeMap<TResult extends Object?>({
+    TResult Function(Preparing value)? preparing,
+    TResult Function(InProgress value)? inProgress,
+    TResult Function(Success value)? success,
+    TResult Function(Failed value)? failed,
+    required TResult orElse(),
   }) {
-    assert(orElse != null);
     if (success != null) {
       return success(this);
     }
@@ -506,10 +486,13 @@ class _$FailedCopyWithImpl<$Res> extends _$UploadStateCopyWithImpl<$Res>
 
   @override
   $Res call({
-    Object error = freezed,
+    Object? error = freezed,
   }) {
     return _then(Failed(
-      error: error == freezed ? _value.error : error as String,
+      error: error == freezed
+          ? _value.error
+          : error // ignore: cast_nullable_to_non_nullable
+              as String,
     ));
   }
 }
@@ -518,7 +501,7 @@ class _$FailedCopyWithImpl<$Res> extends _$UploadStateCopyWithImpl<$Res>
 
 /// @nodoc
 class _$Failed implements Failed {
-  const _$Failed({@required this.error}) : assert(error != null);
+  const _$Failed({required this.error});
 
   factory _$Failed.fromJson(Map<String, dynamic> json) =>
       _$_$FailedFromJson(json);
@@ -550,29 +533,24 @@ class _$Failed implements Failed {
 
   @override
   @optionalTypeArgs
-  TResult when<TResult extends Object>({
-    @required TResult preparing(),
-    @required TResult inProgress(int uploaded, int total),
-    @required TResult success(),
-    @required TResult failed(String error),
+  TResult when<TResult extends Object?>({
+    required TResult Function() preparing,
+    required TResult Function(int uploaded, int total) inProgress,
+    required TResult Function() success,
+    required TResult Function(String error) failed,
   }) {
-    assert(preparing != null);
-    assert(inProgress != null);
-    assert(success != null);
-    assert(failed != null);
     return failed(error);
   }
 
   @override
   @optionalTypeArgs
-  TResult maybeWhen<TResult extends Object>({
-    TResult preparing(),
-    TResult inProgress(int uploaded, int total),
-    TResult success(),
-    TResult failed(String error),
-    @required TResult orElse(),
+  TResult maybeWhen<TResult extends Object?>({
+    TResult Function()? preparing,
+    TResult Function(int uploaded, int total)? inProgress,
+    TResult Function()? success,
+    TResult Function(String error)? failed,
+    required TResult orElse(),
   }) {
-    assert(orElse != null);
     if (failed != null) {
       return failed(error);
     }
@@ -581,29 +559,24 @@ class _$Failed implements Failed {
 
   @override
   @optionalTypeArgs
-  TResult map<TResult extends Object>({
-    @required TResult preparing(Preparing value),
-    @required TResult inProgress(InProgress value),
-    @required TResult success(Success value),
-    @required TResult failed(Failed value),
+  TResult map<TResult extends Object?>({
+    required TResult Function(Preparing value) preparing,
+    required TResult Function(InProgress value) inProgress,
+    required TResult Function(Success value) success,
+    required TResult Function(Failed value) failed,
   }) {
-    assert(preparing != null);
-    assert(inProgress != null);
-    assert(success != null);
-    assert(failed != null);
     return failed(this);
   }
 
   @override
   @optionalTypeArgs
-  TResult maybeMap<TResult extends Object>({
-    TResult preparing(Preparing value),
-    TResult inProgress(InProgress value),
-    TResult success(Success value),
-    TResult failed(Failed value),
-    @required TResult orElse(),
+  TResult maybeMap<TResult extends Object?>({
+    TResult Function(Preparing value)? preparing,
+    TResult Function(InProgress value)? inProgress,
+    TResult Function(Success value)? success,
+    TResult Function(Failed value)? failed,
+    required TResult orElse(),
   }) {
-    assert(orElse != null);
     if (failed != null) {
       return failed(this);
     }
@@ -617,11 +590,11 @@ class _$Failed implements Failed {
 }
 
 abstract class Failed implements UploadState {
-  const factory Failed({@required String error}) = _$Failed;
+  const factory Failed({required String error}) = _$Failed;
 
   factory Failed.fromJson(Map<String, dynamic> json) = _$Failed.fromJson;
 
-  String get error;
+  String get error => throw _privateConstructorUsedError;
   @JsonKey(ignore: true)
-  $FailedCopyWith<Failed> get copyWith;
+  $FailedCopyWith<Failed> get copyWith => throw _privateConstructorUsedError;
 }
diff --git a/packages/stream_chat/lib/src/models/attachment_file.g.dart b/packages/stream_chat/lib/src/models/attachment_file.g.dart
index c6716fba..55fcea6c 100644
--- a/packages/stream_chat/lib/src/models/attachment_file.g.dart
+++ b/packages/stream_chat/lib/src/models/attachment_file.g.dart
@@ -6,12 +6,12 @@ part of 'attachment_file.dart';
 // JsonSerializableGenerator
 // **************************************************************************
 
-AttachmentFile _$AttachmentFileFromJson(Map json) {
+AttachmentFile _$AttachmentFileFromJson(Map<String, dynamic> json) {
   return AttachmentFile(
-    path: json['path'] as String,
-    name: json['name'] as String,
-    bytes: _fromString(json['bytes'] as String),
-    size: json['size'] as int,
+    path: json['path'] as String?,
+    name: json['name'] as String?,
+    bytes: _fromString(json['bytes'] as String?),
+    size: json['size'] as int?,
   );
 }
 
@@ -23,14 +23,14 @@ Map<String, dynamic> _$AttachmentFileToJson(AttachmentFile instance) =>
       'size': instance.size,
     };
 
-_$Preparing _$_$PreparingFromJson(Map json) {
+_$Preparing _$_$PreparingFromJson(Map<String, dynamic> json) {
   return _$Preparing();
 }
 
 Map<String, dynamic> _$_$PreparingToJson(_$Preparing instance) =>
     <String, dynamic>{};
 
-_$InProgress _$_$InProgressFromJson(Map json) {
+_$InProgress _$_$InProgressFromJson(Map<String, dynamic> json) {
   return _$InProgress(
     uploaded: json['uploaded'] as int,
     total: json['total'] as int,
@@ -43,14 +43,14 @@ Map<String, dynamic> _$_$InProgressToJson(_$InProgress instance) =>
       'total': instance.total,
     };
 
-_$Success _$_$SuccessFromJson(Map json) {
+_$Success _$_$SuccessFromJson(Map<String, dynamic> json) {
   return _$Success();
 }
 
 Map<String, dynamic> _$_$SuccessToJson(_$Success instance) =>
     <String, dynamic>{};
 
-_$Failed _$_$FailedFromJson(Map json) {
+_$Failed _$_$FailedFromJson(Map<String, dynamic> json) {
   return _$Failed(
     error: json['error'] as String,
   );
diff --git a/packages/stream_chat/lib/src/models/channel_config.dart b/packages/stream_chat/lib/src/models/channel_config.dart
index 3541573e..9ba36e4f 100644
--- a/packages/stream_chat/lib/src/models/channel_config.dart
+++ b/packages/stream_chat/lib/src/models/channel_config.dart
@@ -1,5 +1,6 @@
 import 'package:json_annotation/json_annotation.dart';
 import 'package:stream_chat/src/models/command.dart';
+
 part 'channel_config.g.dart';
 
 /// The class that contains the information about the configuration of a channel
@@ -7,35 +8,38 @@ part 'channel_config.g.dart';
 class ChannelConfig {
   /// Constructor used for json serialization
   ChannelConfig({
-    this.automod,
-    this.commands,
-    this.connectEvents,
-    this.createdAt,
-    this.updatedAt,
-    this.maxMessageLength,
-    this.messageRetention,
-    this.mutes,
-    this.name,
-    this.reactions,
-    this.readEvents,
-    this.replies,
-    this.search,
-    this.typingEvents,
-    this.uploads,
-    this.urlEnrichment,
-  });
+    this.automod = 'flag',
+    this.commands = const [],
+    this.connectEvents = false,
+    DateTime? createdAt,
+    DateTime? updatedAt,
+    this.maxMessageLength = 0,
+    this.messageRetention = '',
+    this.mutes = false,
+    this.reactions = false,
+    this.readEvents = false,
+    this.replies = false,
+    this.search = false,
+    this.typingEvents = false,
+    this.uploads = false,
+    this.urlEnrichment = false,
+  })  : createdAt = createdAt ?? DateTime.now(),
+        updatedAt = updatedAt ?? DateTime.now();
 
   /// Create a new instance from a json
   factory ChannelConfig.fromJson(Map<String, dynamic> json) =>
       _$ChannelConfigFromJson(json);
 
   /// Moderation configuration
+  @JsonKey(defaultValue: 'flag')
   final String automod;
 
   /// List of available commands
+  @JsonKey(defaultValue: [])
   final List<Command> commands;
 
   /// True if the channel should send connect events
+  @JsonKey(defaultValue: false)
   final bool connectEvents;
 
   /// Date of channel creation
@@ -45,36 +49,43 @@ class ChannelConfig {
   final DateTime updatedAt;
 
   /// Max channel message length
+  @JsonKey(defaultValue: 0)
   final int maxMessageLength;
 
   /// Duration of message retention
+  @JsonKey(defaultValue: '')
   final String messageRetention;
 
   /// True if users can be muted
+  @JsonKey(defaultValue: false)
   final bool mutes;
 
-  /// Name of the channel
-  final String name;
-
   /// True if reaction are active for this channel
+  @JsonKey(defaultValue: false)
   final bool reactions;
 
   /// True if readEvents are active for this channel
+  @JsonKey(defaultValue: false)
   final bool readEvents;
 
   /// True if reply message are active for this channel
+  @JsonKey(defaultValue: false)
   final bool replies;
 
   /// True if it's possible to perform a search in this channel
+  @JsonKey(defaultValue: false)
   final bool search;
 
   /// True if typing events should be sent for this channel
+  @JsonKey(defaultValue: false)
   final bool typingEvents;
 
   /// True if it's possible to upload files to this channel
+  @JsonKey(defaultValue: false)
   final bool uploads;
 
   /// True if urls appears as attachments
+  @JsonKey(defaultValue: false)
   final bool urlEnrichment;
 
   /// Serialize to json
diff --git a/packages/stream_chat/lib/src/models/channel_config.g.dart b/packages/stream_chat/lib/src/models/channel_config.g.dart
index e8152c80..723281c0 100644
--- a/packages/stream_chat/lib/src/models/channel_config.g.dart
+++ b/packages/stream_chat/lib/src/models/channel_config.g.dart
@@ -6,48 +6,43 @@ part of 'channel_config.dart';
 // JsonSerializableGenerator
 // **************************************************************************
 
-ChannelConfig _$ChannelConfigFromJson(Map json) {
+ChannelConfig _$ChannelConfigFromJson(Map<String, dynamic> json) {
   return ChannelConfig(
-    automod: json['automod'] as String,
-    commands: (json['commands'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Command.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList(),
-    connectEvents: json['connect_events'] as bool,
+    automod: json['automod'] as String? ?? 'flag',
+    commands: (json['commands'] as List<dynamic>?)
+            ?.map((e) => Command.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [],
+    connectEvents: json['connect_events'] as bool? ?? false,
     createdAt: json['created_at'] == null
         ? null
         : DateTime.parse(json['created_at'] as String),
     updatedAt: json['updated_at'] == null
         ? null
         : DateTime.parse(json['updated_at'] as String),
-    maxMessageLength: json['max_message_length'] as int,
-    messageRetention: json['message_retention'] as String,
-    mutes: json['mutes'] as bool,
-    name: json['name'] as String,
-    reactions: json['reactions'] as bool,
-    readEvents: json['read_events'] as bool,
-    replies: json['replies'] as bool,
-    search: json['search'] as bool,
-    typingEvents: json['typing_events'] as bool,
-    uploads: json['uploads'] as bool,
-    urlEnrichment: json['url_enrichment'] as bool,
+    maxMessageLength: json['max_message_length'] as int? ?? 0,
+    messageRetention: json['message_retention'] as String? ?? '',
+    mutes: json['mutes'] as bool? ?? false,
+    reactions: json['reactions'] as bool? ?? false,
+    readEvents: json['read_events'] as bool? ?? false,
+    replies: json['replies'] as bool? ?? false,
+    search: json['search'] as bool? ?? false,
+    typingEvents: json['typing_events'] as bool? ?? false,
+    uploads: json['uploads'] as bool? ?? false,
+    urlEnrichment: json['url_enrichment'] as bool? ?? false,
   );
 }
 
 Map<String, dynamic> _$ChannelConfigToJson(ChannelConfig instance) =>
     <String, dynamic>{
       'automod': instance.automod,
-      'commands': instance.commands?.map((e) => e?.toJson())?.toList(),
+      'commands': instance.commands.map((e) => e.toJson()).toList(),
       'connect_events': instance.connectEvents,
-      'created_at': instance.createdAt?.toIso8601String(),
-      'updated_at': instance.updatedAt?.toIso8601String(),
+      'created_at': instance.createdAt.toIso8601String(),
+      'updated_at': instance.updatedAt.toIso8601String(),
       'max_message_length': instance.maxMessageLength,
       'message_retention': instance.messageRetention,
       'mutes': instance.mutes,
-      'name': instance.name,
       'reactions': instance.reactions,
       'read_events': instance.readEvents,
       'replies': instance.replies,
diff --git a/packages/stream_chat/lib/src/models/channel_model.dart b/packages/stream_chat/lib/src/models/channel_model.dart
index 62ea1853..d68edbde 100644
--- a/packages/stream_chat/lib/src/models/channel_model.dart
+++ b/packages/stream_chat/lib/src/models/channel_model.dart
@@ -10,20 +10,29 @@ part 'channel_model.g.dart';
 class ChannelModel {
   /// Constructor used for json serialization
   ChannelModel({
-    this.id,
-    this.type,
-    this.cid,
-    this.config,
+    String? id,
+    String? type,
+    String? cid,
+    ChannelConfig? config,
     this.createdBy,
-    this.frozen,
+    this.frozen = false,
     this.lastMessageAt,
-    this.createdAt,
-    this.updatedAt,
+    DateTime? createdAt,
+    DateTime? updatedAt,
     this.deletedAt,
-    this.memberCount,
+    this.memberCount = 0,
     this.extraData,
     this.team,
-  });
+  })  : config = config ?? ChannelConfig(),
+        createdAt = createdAt ?? DateTime.now(),
+        updatedAt = updatedAt ?? DateTime.now(),
+        assert(
+          cid != null || (id != null && type != null),
+          'provide either a cid or an id and type',
+        ),
+        id = id ?? cid!.split(':')[1],
+        type = type ?? cid!.split(':')[0],
+        cid = cid ?? '$type:$id';
 
   /// Create a new instance from a json
   factory ChannelModel.fromJson(Map<String, dynamic> json) =>
@@ -46,15 +55,15 @@ class ChannelModel {
 
   /// The user that created this channel
   @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
-  final User createdBy;
+  final User? createdBy;
 
   /// True if this channel is frozen
-  @JsonKey(includeIfNull: false)
+  @JsonKey(includeIfNull: false, defaultValue: false)
   final bool frozen;
 
   /// The date of the last message
   @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
-  final DateTime lastMessageAt;
+  final DateTime? lastMessageAt;
 
   /// The date of channel creation
   @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
@@ -66,19 +75,20 @@ class ChannelModel {
 
   /// The date of channel deletion
   @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
-  final DateTime deletedAt;
+  final DateTime? deletedAt;
 
   /// The count of this channel members
-  @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
+  @JsonKey(
+      includeIfNull: false, toJson: Serialization.readOnly, defaultValue: 0)
   final int memberCount;
 
   /// Map of custom channel extraData
   @JsonKey(includeIfNull: false)
-  final Map<String, dynamic> extraData;
+  final Map<String, dynamic>? extraData;
 
   /// The team the channel belongs to
   @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
-  final String team;
+  final String? team;
 
   /// Known top level fields.
   /// Useful for [Serialization] methods.
@@ -98,30 +108,29 @@ class ChannelModel {
   ];
 
   /// Shortcut for channel name
-  String get name =>
-      extraData?.containsKey('name') == true ? extraData['name'] : cid;
+  String? get name =>
+      extraData?.containsKey('name') == true ? extraData!['name'] : cid;
 
   /// Serialize to json
   Map<String, dynamic> toJson() => Serialization.moveFromExtraDataToRoot(
         _$ChannelModelToJson(this),
-        topLevelFields,
       );
 
   /// Creates a copy of [ChannelModel] with specified attributes overridden.
   ChannelModel copyWith({
-    String id,
-    String type,
-    String cid,
-    ChannelConfig config,
-    User createdBy,
-    bool frozen,
-    DateTime lastMessageAt,
-    DateTime createdAt,
-    DateTime updatedAt,
-    DateTime deletedAt,
-    int memberCount,
-    Map<String, dynamic> extraData,
-    String team,
+    String? id,
+    String? type,
+    String? cid,
+    ChannelConfig? config,
+    User? createdBy,
+    bool? frozen,
+    DateTime? lastMessageAt,
+    DateTime? createdAt,
+    DateTime? updatedAt,
+    DateTime? deletedAt,
+    int? memberCount,
+    Map<String, dynamic>? extraData,
+    String? team,
   }) =>
       ChannelModel(
         id: id ?? this.id,
@@ -141,7 +150,7 @@ class ChannelModel {
 
   /// Returns a new [ChannelModel] that is a combination of this channelModel
   /// and the given [other] channelModel.
-  ChannelModel merge(ChannelModel other) {
+  ChannelModel merge(ChannelModel? other) {
     if (other == null) return this;
     return copyWith(
       id: other.id,
diff --git a/packages/stream_chat/lib/src/models/channel_model.g.dart b/packages/stream_chat/lib/src/models/channel_model.g.dart
index 4f535f46..e71112b6 100644
--- a/packages/stream_chat/lib/src/models/channel_model.g.dart
+++ b/packages/stream_chat/lib/src/models/channel_model.g.dart
@@ -6,22 +6,18 @@ part of 'channel_model.dart';
 // JsonSerializableGenerator
 // **************************************************************************
 
-ChannelModel _$ChannelModelFromJson(Map json) {
+ChannelModel _$ChannelModelFromJson(Map<String, dynamic> json) {
   return ChannelModel(
-    id: json['id'] as String,
-    type: json['type'] as String,
-    cid: json['cid'] as String,
+    id: json['id'] as String?,
+    type: json['type'] as String?,
+    cid: json['cid'] as String?,
     config: json['config'] == null
         ? null
-        : ChannelConfig.fromJson((json['config'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
+        : ChannelConfig.fromJson(json['config'] as Map<String, dynamic>),
     createdBy: json['created_by'] == null
         ? null
-        : User.fromJson((json['created_by'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
-    frozen: json['frozen'] as bool,
+        : User.fromJson(json['created_by'] as Map<String, dynamic>),
+    frozen: json['frozen'] as bool? ?? false,
     lastMessageAt: json['last_message_at'] == null
         ? null
         : DateTime.parse(json['last_message_at'] as String),
@@ -34,11 +30,9 @@ ChannelModel _$ChannelModelFromJson(Map json) {
     deletedAt: json['deleted_at'] == null
         ? null
         : DateTime.parse(json['deleted_at'] as String),
-    memberCount: json['member_count'] as int,
-    extraData: (json['extra_data'] as Map)?.map(
-      (k, e) => MapEntry(k as String, e),
-    ),
-    team: json['team'] as String,
+    memberCount: json['member_count'] as int? ?? 0,
+    extraData: json['extra_data'] as Map<String, dynamic>?,
+    team: json['team'] as String?,
   );
 }
 
@@ -57,7 +51,7 @@ Map<String, dynamic> _$ChannelModelToJson(ChannelModel instance) {
   writeNotNull('cid', readonly(instance.cid));
   writeNotNull('config', readonly(instance.config));
   writeNotNull('created_by', readonly(instance.createdBy));
-  writeNotNull('frozen', instance.frozen);
+  val['frozen'] = instance.frozen;
   writeNotNull('last_message_at', readonly(instance.lastMessageAt));
   writeNotNull('created_at', readonly(instance.createdAt));
   writeNotNull('updated_at', readonly(instance.updatedAt));
diff --git a/packages/stream_chat/lib/src/models/channel_state.dart b/packages/stream_chat/lib/src/models/channel_state.dart
index 3a1f3178..9d18f434 100644
--- a/packages/stream_chat/lib/src/models/channel_state.dart
+++ b/packages/stream_chat/lib/src/models/channel_state.dart
@@ -22,24 +22,29 @@ class ChannelState {
   });
 
   /// The channel to which this state belongs
-  final ChannelModel channel;
+  final ChannelModel? channel;
 
   /// A paginated list of channel messages
+  @JsonKey(defaultValue: <Message>[])
   final List<Message> messages;
 
   /// A paginated list of channel members
+  @JsonKey(defaultValue: <Member>[])
   final List<Member> members;
 
   /// A paginated list of pinned messages
+  @JsonKey(defaultValue: <Message>[])
   final List<Message> pinnedMessages;
 
   /// The count of users watching the channel
-  final int watcherCount;
+  final int? watcherCount;
 
   /// A paginated list of users watching the channel
+  @JsonKey(defaultValue: <User>[])
   final List<User> watchers;
 
   /// The list of channel reads
+  @JsonKey(defaultValue: <Read>[])
   final List<Read> read;
 
   /// Create a new instance from a json
@@ -51,13 +56,13 @@ class ChannelState {
 
   /// Creates a copy of [ChannelState] with specified attributes overridden.
   ChannelState copyWith({
-    ChannelModel channel,
-    List<Message> messages,
-    List<Member> members,
-    List<Message> pinnedMessages,
-    int watcherCount,
-    List<User> watchers,
-    List<Read> read,
+    ChannelModel? channel,
+    List<Message>? messages,
+    List<Member>? members,
+    List<Message>? pinnedMessages,
+    int? watcherCount,
+    List<User>? watchers,
+    List<Read>? read,
   }) =>
       ChannelState(
         channel: channel ?? this.channel,
diff --git a/packages/stream_chat/lib/src/models/channel_state.g.dart b/packages/stream_chat/lib/src/models/channel_state.g.dart
index a66899a4..39c6373f 100644
--- a/packages/stream_chat/lib/src/models/channel_state.g.dart
+++ b/packages/stream_chat/lib/src/models/channel_state.g.dart
@@ -6,60 +6,43 @@ part of 'channel_state.dart';
 // JsonSerializableGenerator
 // **************************************************************************
 
-ChannelState _$ChannelStateFromJson(Map json) {
+ChannelState _$ChannelStateFromJson(Map<String, dynamic> json) {
   return ChannelState(
     channel: json['channel'] == null
         ? null
-        : ChannelModel.fromJson((json['channel'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
-    messages: (json['messages'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Message.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList(),
-    members: (json['members'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Member.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList(),
-    pinnedMessages: (json['pinned_messages'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Message.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList(),
-    watcherCount: json['watcher_count'] as int,
-    watchers: (json['watchers'] as List)
-        ?.map((e) => e == null
-            ? null
-            : User.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList(),
-    read: (json['read'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Read.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList(),
+        : ChannelModel.fromJson(json['channel'] as Map<String, dynamic>),
+    messages: (json['messages'] as List<dynamic>?)
+            ?.map((e) => Message.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [],
+    members: (json['members'] as List<dynamic>?)
+            ?.map((e) => Member.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [],
+    pinnedMessages: (json['pinned_messages'] as List<dynamic>?)
+            ?.map((e) => Message.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [],
+    watcherCount: json['watcher_count'] as int?,
+    watchers: (json['watchers'] as List<dynamic>?)
+            ?.map((e) => User.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [],
+    read: (json['read'] as List<dynamic>?)
+            ?.map((e) => Read.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [],
   );
 }
 
 Map<String, dynamic> _$ChannelStateToJson(ChannelState instance) =>
     <String, dynamic>{
       'channel': instance.channel?.toJson(),
-      'messages': instance.messages?.map((e) => e?.toJson())?.toList(),
-      'members': instance.members?.map((e) => e?.toJson())?.toList(),
+      'messages': instance.messages.map((e) => e.toJson()).toList(),
+      'members': instance.members.map((e) => e.toJson()).toList(),
       'pinned_messages':
-          instance.pinnedMessages?.map((e) => e?.toJson())?.toList(),
+          instance.pinnedMessages.map((e) => e.toJson()).toList(),
       'watcher_count': instance.watcherCount,
-      'watchers': instance.watchers?.map((e) => e?.toJson())?.toList(),
-      'read': instance.read?.map((e) => e?.toJson())?.toList(),
+      'watchers': instance.watchers.map((e) => e.toJson()).toList(),
+      'read': instance.read.map((e) => e.toJson()).toList(),
     };
diff --git a/packages/stream_chat/lib/src/models/command.dart b/packages/stream_chat/lib/src/models/command.dart
index a5ababd2..5ba0043c 100644
--- a/packages/stream_chat/lib/src/models/command.dart
+++ b/packages/stream_chat/lib/src/models/command.dart
@@ -7,9 +7,9 @@ part 'command.g.dart';
 class Command {
   /// Constructor used for json serialization
   Command({
-    this.name,
-    this.description,
-    this.args,
+    required this.name,
+    required this.description,
+    required this.args,
   });
 
   /// Create a new instance from a json
diff --git a/packages/stream_chat/lib/src/models/command.g.dart b/packages/stream_chat/lib/src/models/command.g.dart
index f32e8e8a..cf8be971 100644
--- a/packages/stream_chat/lib/src/models/command.g.dart
+++ b/packages/stream_chat/lib/src/models/command.g.dart
@@ -6,7 +6,7 @@ part of 'command.dart';
 // JsonSerializableGenerator
 // **************************************************************************
 
-Command _$CommandFromJson(Map json) {
+Command _$CommandFromJson(Map<String, dynamic> json) {
   return Command(
     name: json['name'] as String,
     description: json['description'] as String,
diff --git a/packages/stream_chat/lib/src/models/device.dart b/packages/stream_chat/lib/src/models/device.dart
index 150e6759..5dc98d25 100644
--- a/packages/stream_chat/lib/src/models/device.dart
+++ b/packages/stream_chat/lib/src/models/device.dart
@@ -7,8 +7,8 @@ part 'device.g.dart';
 class Device {
   /// Constructor used for json serialization
   Device({
-    this.id,
-    this.pushProvider,
+    required this.id,
+    required this.pushProvider,
   });
 
   /// Create a new instance from a json
diff --git a/packages/stream_chat/lib/src/models/device.g.dart b/packages/stream_chat/lib/src/models/device.g.dart
index bac60856..5fcd9435 100644
--- a/packages/stream_chat/lib/src/models/device.g.dart
+++ b/packages/stream_chat/lib/src/models/device.g.dart
@@ -6,7 +6,7 @@ part of 'device.dart';
 // JsonSerializableGenerator
 // **************************************************************************
 
-Device _$DeviceFromJson(Map json) {
+Device _$DeviceFromJson(Map<String, dynamic> json) {
   return Device(
     id: json['id'] as String,
     pushProvider: json['push_provider'] as String,
diff --git a/packages/stream_chat/lib/src/models/event.dart b/packages/stream_chat/lib/src/models/event.dart
index 28cf1b38..7e57de60 100644
--- a/packages/stream_chat/lib/src/models/event.dart
+++ b/packages/stream_chat/lib/src/models/event.dart
@@ -10,7 +10,7 @@ part 'event.g.dart';
 @JsonSerializable()
 class Event {
   /// Constructor used for json serialization
-  Event({
+  const Event({
     this.type,
     this.cid,
     this.connectionId,
@@ -27,71 +27,72 @@ class Event {
     this.channelId,
     this.channelType,
     this.parentId,
-    this.extraData,
-  }) : isLocal = true;
+    this.extraData = const {},
+    this.isLocal = true,
+  });
 
   /// Create a new instance from a json
   factory Event.fromJson(Map<String, dynamic> json) =>
       _$EventFromJson(Serialization.moveToExtraDataFromRoot(
         json,
         topLevelFields,
-      ))
-        ..isLocal = false;
+      ));
 
   /// The type of the event
   /// [EventType] contains some predefined constant types
-  final String type;
+  final String? type;
 
   /// The channel cid to which the event belongs
-  final String cid;
+  final String? cid;
 
   /// The channel id to which the event belongs
-  final String channelId;
+  final String? channelId;
 
   /// The channel type to which the event belongs
-  final String channelType;
+  final String? channelType;
 
   /// The connection id in which the event has been sent
-  final String connectionId;
+  final String? connectionId;
 
   /// The date of creation of the event
-  final DateTime createdAt;
+  final DateTime? createdAt;
 
   /// User object of the health check user
-  final OwnUser me;
+  final OwnUser? me;
 
   /// User object of the current user
-  final User user;
+  final User? user;
 
   /// The message sent with the event
-  final Message message;
+  final Message? message;
 
   /// The channel sent with the event
-  final EventChannel channel;
+  final EventChannel? channel;
 
   /// The member sent with the event
-  final Member member;
+  final Member? member;
 
   /// The reaction sent with the event
-  final Reaction reaction;
+  final Reaction? reaction;
 
   /// The number of unread messages for current user
-  final int totalUnreadCount;
+  final int? totalUnreadCount;
 
   /// User total unread channels
-  final int unreadChannels;
+  final int? unreadChannels;
 
   /// Online status
-  final bool online;
+  final bool? online;
 
   /// The id of the parent message of a thread
-  final String parentId;
+  final String? parentId;
 
   /// True if the event is generated by this client
-  bool isLocal;
+  @JsonKey(defaultValue: false)
+  final bool isLocal;
 
   /// Map of custom channel extraData
-  @JsonKey(includeIfNull: false)
+  @JsonKey(defaultValue: {})
   final Map<String, dynamic> extraData;
 
   /// Known top level fields.
@@ -119,28 +120,27 @@ class Event {
   /// Serialize to json
   Map<String, dynamic> toJson() => Serialization.moveFromExtraDataToRoot(
         _$EventToJson(this),
-        topLevelFields,
       );
 
   /// Creates a copy of [Event] with specified attributes overridden.
   Event copyWith({
-    String type,
-    String cid,
-    String channelId,
-    String channelType,
-    String connectionId,
-    DateTime createdAt,
-    OwnUser me,
-    User user,
-    Message message,
-    EventChannel channel,
-    Member member,
-    Reaction reaction,
-    int totalUnreadCount,
-    int unreadChannels,
-    bool online,
-    String parentId,
-    Map<String, dynamic> extraData,
+    String? type,
+    String? cid,
+    String? channelId,
+    String? channelType,
+    String? connectionId,
+    DateTime? createdAt,
+    OwnUser? me,
+    User? user,
+    Message? message,
+    EventChannel? channel,
+    Member? member,
+    Reaction? reaction,
+    int? totalUnreadCount,
+    int? unreadChannels,
+    bool? online,
+    String? parentId,
+    Map<String, dynamic>? extraData,
   }) =>
       Event(
         type: type ?? this.type,
@@ -169,18 +169,18 @@ class EventChannel extends ChannelModel {
   /// Constructor used for json serialization
   EventChannel({
     this.members,
-    String id,
-    String type,
-    String cid,
-    ChannelConfig config,
-    User createdBy,
-    bool frozen,
-    DateTime lastMessageAt,
-    DateTime createdAt,
-    DateTime updatedAt,
-    DateTime deletedAt,
-    int memberCount,
-    Map<String, dynamic> extraData,
+    String? id,
+    String? type,
+    required String cid,
+    required ChannelConfig config,
+    User? createdBy,
+    bool frozen = false,
+    DateTime? lastMessageAt,
+    required DateTime createdAt,
+    required DateTime updatedAt,
+    DateTime? deletedAt,
+    required int memberCount,
+    Map<String, dynamic>? extraData,
   }) : super(
           id: id,
           type: type,
@@ -204,7 +204,7 @@ class EventChannel extends ChannelModel {
       ));
 
   /// A paginated list of channel members
-  final List<Member> members;
+  final List<Member>? members;
 
   /// Known top level fields.
   /// Useful for [Serialization] methods.
@@ -217,6 +217,5 @@ class EventChannel extends ChannelModel {
   @override
   Map<String, dynamic> toJson() => Serialization.moveFromExtraDataToRoot(
         _$EventChannelToJson(this),
-        topLevelFields,
       );
 }
diff --git a/packages/stream_chat/lib/src/models/event.g.dart b/packages/stream_chat/lib/src/models/event.g.dart
index aaef8181..d0bb0d87 100644
--- a/packages/stream_chat/lib/src/models/event.g.dart
+++ b/packages/stream_chat/lib/src/models/event.g.dart
@@ -6,126 +6,87 @@ part of 'event.dart';
 // JsonSerializableGenerator
 // **************************************************************************
 
-Event _$EventFromJson(Map json) {
+Event _$EventFromJson(Map<String, dynamic> json) {
   return Event(
-    type: json['type'] as String,
-    cid: json['cid'] as String,
-    connectionId: json['connection_id'] as String,
+    type: json['type'] as String?,
+    cid: json['cid'] as String?,
+    connectionId: json['connection_id'] as String?,
     createdAt: json['created_at'] == null
         ? null
         : DateTime.parse(json['created_at'] as String),
     me: json['me'] == null
         ? null
-        : OwnUser.fromJson((json['me'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
+        : OwnUser.fromJson(json['me'] as Map<String, dynamic>),
     user: json['user'] == null
         ? null
-        : User.fromJson((json['user'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
+        : User.fromJson(json['user'] as Map<String, dynamic>),
     message: json['message'] == null
         ? null
-        : Message.fromJson((json['message'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
-    totalUnreadCount: json['total_unread_count'] as int,
-    unreadChannels: json['unread_channels'] as int,
+        : Message.fromJson(json['message'] as Map<String, dynamic>),
+    totalUnreadCount: json['total_unread_count'] as int?,
+    unreadChannels: json['unread_channels'] as int?,
     reaction: json['reaction'] == null
         ? null
-        : Reaction.fromJson((json['reaction'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
-    online: json['online'] as bool,
+        : Reaction.fromJson(json['reaction'] as Map<String, dynamic>),
+    online: json['online'] as bool?,
     channel: json['channel'] == null
         ? null
-        : EventChannel.fromJson((json['channel'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
+        : EventChannel.fromJson(json['channel'] as Map<String, dynamic>),
     member: json['member'] == null
         ? null
-        : Member.fromJson((json['member'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
-    channelId: json['channel_id'] as String,
-    channelType: json['channel_type'] as String,
-    parentId: json['parent_id'] as String,
-    extraData: (json['extra_data'] as Map)?.map(
-      (k, e) => MapEntry(k as String, e),
-    ),
-  )..isLocal = json['is_local'] as bool;
+        : Member.fromJson(json['member'] as Map<String, dynamic>),
+    channelId: json['channel_id'] as String?,
+    channelType: json['channel_type'] as String?,
+    parentId: json['parent_id'] as String?,
+    extraData: json['extra_data'] as Map<String, dynamic>? ?? {},
+    isLocal: json['is_local'] as bool? ?? false,
+  );
 }
 
-Map<String, dynamic> _$EventToJson(Event instance) {
-  final val = <String, dynamic>{
-    'type': instance.type,
-    'cid': instance.cid,
-    'channel_id': instance.channelId,
-    'channel_type': instance.channelType,
-    'connection_id': instance.connectionId,
-    'created_at': instance.createdAt?.toIso8601String(),
-    'me': instance.me?.toJson(),
-    'user': instance.user?.toJson(),
-    'message': instance.message?.toJson(),
-    'channel': instance.channel?.toJson(),
-    'member': instance.member?.toJson(),
-    'reaction': instance.reaction?.toJson(),
-    'total_unread_count': instance.totalUnreadCount,
-    'unread_channels': instance.unreadChannels,
-    'online': instance.online,
-    'parent_id': instance.parentId,
-    'is_local': instance.isLocal,
-  };
+Map<String, dynamic> _$EventToJson(Event instance) => <String, dynamic>{
+      'type': instance.type,
+      'cid': instance.cid,
+      'channel_id': instance.channelId,
+      'channel_type': instance.channelType,
+      'connection_id': instance.connectionId,
+      'created_at': instance.createdAt?.toIso8601String(),
+      'me': instance.me?.toJson(),
+      'user': instance.user?.toJson(),
+      'message': instance.message?.toJson(),
+      'channel': instance.channel?.toJson(),
+      'member': instance.member?.toJson(),
+      'reaction': instance.reaction?.toJson(),
+      'total_unread_count': instance.totalUnreadCount,
+      'unread_channels': instance.unreadChannels,
+      'online': instance.online,
+      'parent_id': instance.parentId,
+      'is_local': instance.isLocal,
+      'extra_data': instance.extraData,
+    };
 
-  void writeNotNull(String key, dynamic value) {
-    if (value != null) {
-      val[key] = value;
-    }
-  }
-
-  writeNotNull('extra_data', instance.extraData);
-  return val;
-}
-
-EventChannel _$EventChannelFromJson(Map json) {
+EventChannel _$EventChannelFromJson(Map<String, dynamic> json) {
   return EventChannel(
-    members: (json['members'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Member.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList(),
-    id: json['id'] as String,
-    type: json['type'] as String,
+    members: (json['members'] as List<dynamic>?)
+        ?.map((e) => Member.fromJson(e as Map<String, dynamic>))
+        .toList(),
+    id: json['id'] as String?,
+    type: json['type'] as String?,
     cid: json['cid'] as String,
-    config: json['config'] == null
-        ? null
-        : ChannelConfig.fromJson((json['config'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
+    config: ChannelConfig.fromJson(json['config'] as Map<String, dynamic>),
     createdBy: json['created_by'] == null
         ? null
-        : User.fromJson((json['created_by'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
-    frozen: json['frozen'] as bool,
+        : User.fromJson(json['created_by'] as Map<String, dynamic>),
+    frozen: json['frozen'] as bool? ?? false,
     lastMessageAt: json['last_message_at'] == null
         ? null
         : DateTime.parse(json['last_message_at'] as String),
-    createdAt: json['created_at'] == null
-        ? null
-        : DateTime.parse(json['created_at'] as String),
-    updatedAt: json['updated_at'] == null
-        ? null
-        : DateTime.parse(json['updated_at'] as String),
+    createdAt: DateTime.parse(json['created_at'] as String),
+    updatedAt: DateTime.parse(json['updated_at'] as String),
     deletedAt: json['deleted_at'] == null
         ? null
         : DateTime.parse(json['deleted_at'] as String),
-    memberCount: json['member_count'] as int,
-    extraData: (json['extra_data'] as Map)?.map(
-      (k, e) => MapEntry(k as String, e),
-    ),
+    memberCount: json['member_count'] as int? ?? 0,
+    extraData: json['extra_data'] as Map<String, dynamic>?,
   );
 }
 
@@ -144,13 +105,13 @@ Map<String, dynamic> _$EventChannelToJson(EventChannel instance) {
   writeNotNull('cid', readonly(instance.cid));
   writeNotNull('config', readonly(instance.config));
   writeNotNull('created_by', readonly(instance.createdBy));
-  writeNotNull('frozen', instance.frozen);
+  val['frozen'] = instance.frozen;
   writeNotNull('last_message_at', readonly(instance.lastMessageAt));
   writeNotNull('created_at', readonly(instance.createdAt));
   writeNotNull('updated_at', readonly(instance.updatedAt));
   writeNotNull('deleted_at', readonly(instance.deletedAt));
   writeNotNull('member_count', readonly(instance.memberCount));
   writeNotNull('extra_data', instance.extraData);
-  val['members'] = instance.members?.map((e) => e?.toJson())?.toList();
+  val['members'] = instance.members?.map((e) => e.toJson()).toList();
   return val;
 }
diff --git a/packages/stream_chat/lib/src/models/member.dart b/packages/stream_chat/lib/src/models/member.dart
index e99d8d34..49df170c 100644
--- a/packages/stream_chat/lib/src/models/member.dart
+++ b/packages/stream_chat/lib/src/models/member.dart
@@ -12,15 +12,16 @@ class Member {
     this.user,
     this.inviteAcceptedAt,
     this.inviteRejectedAt,
-    this.invited,
+    this.invited = false,
     this.role,
     this.userId,
-    this.isModerator,
-    this.createdAt,
-    this.updatedAt,
-    this.banned,
-    this.shadowBanned,
-  });
+    this.isModerator = false,
+    DateTime? createdAt,
+    DateTime? updatedAt,
+    this.banned = false,
+    this.shadowBanned = false,
+  })  : createdAt = createdAt ?? DateTime.now(),
+        updatedAt = updatedAt ?? DateTime.now();
 
   /// Create a new instance from a json
   factory Member.fromJson(Map<String, dynamic> json) {
@@ -31,30 +32,34 @@ class Member {
   }
 
   /// The interested user
-  final User user;
+  final User? user;
 
   /// The date in which the user accepted the invite to the channel
-  final DateTime inviteAcceptedAt;
+  final DateTime? inviteAcceptedAt;
 
   /// The date in which the user rejected the invite to the channel
-  final DateTime inviteRejectedAt;
+  final DateTime? inviteRejectedAt;
 
   /// True if the user has been invited to the channel
+  @JsonKey(defaultValue: false)
   final bool invited;
 
   /// The role of the user in the channel
-  final String role;
+  final String? role;
 
   /// The id of the interested user
-  final String userId;
+  final String? userId;
 
   /// True if the user is a moderator of the channel
+  @JsonKey(defaultValue: false)
   final bool isModerator;
 
   /// True if the member is banned from the channel
+  @JsonKey(defaultValue: false)
   final bool banned;
 
   /// True if the member is shadow banned from the channel
+  @JsonKey(defaultValue: false)
   final bool shadowBanned;
 
   /// The date of creation
@@ -65,17 +70,17 @@ class Member {
 
   /// Creates a copy of [Member] with specified attributes overridden.
   Member copyWith({
-    User user,
-    DateTime inviteAcceptedAt,
-    DateTime inviteRejectedAt,
-    bool invited,
-    String role,
-    String userId,
-    bool isModerator,
-    DateTime createdAt,
-    DateTime updatedAt,
-    bool banned,
-    bool shadowBanned,
+    User? user,
+    DateTime? inviteAcceptedAt,
+    DateTime? inviteRejectedAt,
+    bool? invited,
+    String? role,
+    String? userId,
+    bool? isModerator,
+    DateTime? createdAt,
+    DateTime? updatedAt,
+    bool? banned,
+    bool? shadowBanned,
   }) =>
       Member(
         user: user ?? this.user,
diff --git a/packages/stream_chat/lib/src/models/member.g.dart b/packages/stream_chat/lib/src/models/member.g.dart
index 3ac8778e..a75b458d 100644
--- a/packages/stream_chat/lib/src/models/member.g.dart
+++ b/packages/stream_chat/lib/src/models/member.g.dart
@@ -6,31 +6,29 @@ part of 'member.dart';
 // JsonSerializableGenerator
 // **************************************************************************
 
-Member _$MemberFromJson(Map json) {
+Member _$MemberFromJson(Map<String, dynamic> json) {
   return Member(
     user: json['user'] == null
         ? null
-        : User.fromJson((json['user'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
+        : User.fromJson(json['user'] as Map<String, dynamic>),
     inviteAcceptedAt: json['invite_accepted_at'] == null
         ? null
         : DateTime.parse(json['invite_accepted_at'] as String),
     inviteRejectedAt: json['invite_rejected_at'] == null
         ? null
         : DateTime.parse(json['invite_rejected_at'] as String),
-    invited: json['invited'] as bool,
-    role: json['role'] as String,
-    userId: json['user_id'] as String,
-    isModerator: json['is_moderator'] as bool,
+    invited: json['invited'] as bool? ?? false,
+    role: json['role'] as String?,
+    userId: json['user_id'] as String?,
+    isModerator: json['is_moderator'] as bool? ?? false,
     createdAt: json['created_at'] == null
         ? null
         : DateTime.parse(json['created_at'] as String),
     updatedAt: json['updated_at'] == null
         ? null
         : DateTime.parse(json['updated_at'] as String),
-    banned: json['banned'] as bool,
-    shadowBanned: json['shadow_banned'] as bool,
+    banned: json['banned'] as bool? ?? false,
+    shadowBanned: json['shadow_banned'] as bool? ?? false,
   );
 }
 
@@ -44,6 +42,6 @@ Map<String, dynamic> _$MemberToJson(Member instance) => <String, dynamic>{
       'is_moderator': instance.isModerator,
       'banned': instance.banned,
       'shadow_banned': instance.shadowBanned,
-      'created_at': instance.createdAt?.toIso8601String(),
-      'updated_at': instance.updatedAt?.toIso8601String(),
+      'created_at': instance.createdAt.toIso8601String(),
+      'updated_at': instance.updatedAt.toIso8601String(),
     };
diff --git a/packages/stream_chat/lib/src/models/message.dart b/packages/stream_chat/lib/src/models/message.dart
index 68264f8d..03a162c5 100644
--- a/packages/stream_chat/lib/src/models/message.dart
+++ b/packages/stream_chat/lib/src/models/message.dart
@@ -45,13 +45,13 @@ enum MessageSendingStatus {
 class Message extends Equatable {
   /// Constructor used for json serialization
   Message({
-    String id,
+    String? id,
     this.text,
-    this.type,
-    this.attachments,
-    this.mentionedUsers,
-    this.silent,
-    this.shadowed,
+    this.type = 'regular',
+    this.attachments = const [],
+    this.mentionedUsers = const [],
+    this.silent = false,
+    this.shadowed = false,
     this.reactionCounts,
     this.reactionScores,
     this.latestReactions,
@@ -63,19 +63,21 @@ class Message extends Equatable {
     this.threadParticipants,
     this.showInChannel,
     this.command,
-    this.createdAt,
-    this.updatedAt,
+    DateTime? createdAt,
+    DateTime? updatedAt,
     this.user,
     this.pinned = false,
     this.pinnedAt,
-    DateTime pinExpires,
+    DateTime? pinExpires,
     this.pinnedBy,
-    this.extraData,
+    this.extraData = const {},
     this.deletedAt,
     this.status = MessageSendingStatus.sent,
-    this.skipPush,
+    this.skipPush = false,
   })  : id = id ?? const Uuid().v4(),
-        pinExpires = pinExpires?.toUtc();
+        pinExpires = pinExpires?.toUtc(),
+        createdAt = createdAt ?? DateTime.now(),
+        updatedAt = updatedAt ?? DateTime.now();
 
   /// Create a new instance from a json
   factory Message.fromJson(Map<String, dynamic> json) => _$MessageFromJson(
@@ -86,75 +88,91 @@ class Message extends Equatable {
   final String id;
 
   /// The text of this message
-  final String text;
+  final String? text;
 
   /// The status of a sending message
   @JsonKey(ignore: true)
   final MessageSendingStatus status;
 
   /// The message type
-  @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
+  @JsonKey(
+    includeIfNull: false,
+    toJson: Serialization.readOnly,
+    defaultValue: 'regular',
+  )
   final String type;
 
   /// The list of attachments, either provided by the user or generated from a
   /// command or as a result of URL scraping.
-  @JsonKey(includeIfNull: false)
+  @JsonKey(
+    includeIfNull: false,
+    defaultValue: [],
+  )
   final List<Attachment> attachments;
 
   /// The list of user mentioned in the message
-  @JsonKey(toJson: Serialization.userIds)
+  @JsonKey(
+    toJson: Serialization.userIds,
+    defaultValue: [],
+  )
   final List<User> mentionedUsers;
 
   /// A map describing the count of number of every reaction
   @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
-  final Map<String, int> reactionCounts;
+  final Map<String, int>? reactionCounts;
 
   /// A map describing the count of score of every reaction
   @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
-  final Map<String, int> reactionScores;
+  final Map<String, int>? reactionScores;
 
   /// The latest reactions to the message created by any user.
   @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
-  final List<Reaction> latestReactions;
+  final List<Reaction>? latestReactions;
 
   /// The reactions added to the message by the current user.
   @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
-  final List<Reaction> ownReactions;
+  final List<Reaction>? ownReactions;
 
   /// The ID of the parent message, if the message is a thread reply.
-  final String parentId;
+  final String? parentId;
 
   /// A quoted reply message
   @JsonKey(toJson: Serialization.readOnly)
-  final Message quotedMessage;
+  final Message? quotedMessage;
 
   /// The ID of the quoted message, if the message is a quoted reply.
-  final String quotedMessageId;
+  final String? quotedMessageId;
 
   /// Reserved field indicating the number of replies for this message.
   @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
-  final int replyCount;
+  final int? replyCount;
 
   /// Reserved field indicating the thread participants for this message.
   @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
-  final List<User> threadParticipants;
+  final List<User>? threadParticipants;
 
   /// Check if this message needs to show in the channel.
-  final bool showInChannel;
+  final bool? showInChannel;
 
   /// If true the message is silent
+  @JsonKey(defaultValue: false)
   final bool silent;
 
   /// If true the message will not send a push notification
+  @JsonKey(defaultValue: false)
   final bool skipPush;
 
   /// If true the message is shadowed
-  @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
+  @JsonKey(
+    includeIfNull: false,
+    toJson: Serialization.readOnly,
+    defaultValue: false,
+  )
   final bool shadowed;
 
   /// A used command name.
   @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
-  final String command;
+  final String? command;
 
   /// Reserved field indicating when the message was created.
   @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
@@ -166,26 +184,30 @@ class Message extends Equatable {
 
   /// User who sent the message
   @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
-  final User user;
+  final User? user;
 
   /// If true the message is pinned
+  @JsonKey(defaultValue: false)
   final bool pinned;
 
   /// Reserved field indicating when the message was pinned
   @JsonKey(toJson: Serialization.readOnly)
-  final DateTime pinnedAt;
+  final DateTime? pinnedAt;
 
   /// Reserved field indicating when the message will expire
   ///
   /// if `null` message has no expiry
-  final DateTime pinExpires;
+  final DateTime? pinExpires;
 
   /// Reserved field indicating who pinned the message
   @JsonKey(toJson: Serialization.readOnly)
-  final User pinnedBy;
+  final User? pinnedBy;
 
   /// Message custom extraData
-  @JsonKey(includeIfNull: false)
+  @JsonKey(
+    includeIfNull: false,
+    defaultValue: {},
+  )
   final Map<String, dynamic> extraData;
 
   /// True if the message is a system info
@@ -199,7 +221,7 @@ class Message extends Equatable {
 
   /// Reserved field indicating when the message was deleted.
   @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
-  final DateTime deletedAt;
+  final DateTime? deletedAt;
 
   /// Known top level fields.
   /// Useful for [Serialization] methods.
@@ -236,39 +258,40 @@ class Message extends Equatable {
 
   /// Serialize to json
   Map<String, dynamic> toJson() => Serialization.moveFromExtraDataToRoot(
-      _$MessageToJson(this), topLevelFields);
+        _$MessageToJson(this),
+      );
 
   /// Creates a copy of [Message] with specified attributes overridden.
   Message copyWith({
-    String id,
-    String text,
-    String type,
-    List<Attachment> attachments,
-    List<User> mentionedUsers,
-    Map<String, int> reactionCounts,
-    Map<String, int> reactionScores,
-    List<Reaction> latestReactions,
-    List<Reaction> ownReactions,
-    String parentId,
-    Message quotedMessage,
-    String quotedMessageId,
-    int replyCount,
-    List<User> threadParticipants,
-    bool showInChannel,
-    bool shadowed,
-    bool silent,
-    String command,
-    DateTime createdAt,
-    DateTime updatedAt,
-    DateTime deletedAt,
-    User user,
-    bool pinned,
-    DateTime pinnedAt,
-    Object pinExpires = _pinExpires,
-    User pinnedBy,
-    Map<String, dynamic> extraData,
-    MessageSendingStatus status,
-    bool skipPush,
+    String? id,
+    String? text,
+    String? type,
+    List<Attachment>? attachments,
+    List<User>? mentionedUsers,
+    Map<String, int>? reactionCounts,
+    Map<String, int>? reactionScores,
+    List<Reaction>? latestReactions,
+    List<Reaction>? ownReactions,
+    String? parentId,
+    Message? quotedMessage,
+    String? quotedMessageId,
+    int? replyCount,
+    List<User>? threadParticipants,
+    bool? showInChannel,
+    bool? shadowed,
+    bool? silent,
+    String? command,
+    DateTime? createdAt,
+    DateTime? updatedAt,
+    DateTime? deletedAt,
+    User? user,
+    bool? pinned,
+    DateTime? pinnedAt,
+    Object? pinExpires = _pinExpires,
+    User? pinnedBy,
+    Map<String, dynamic>? extraData,
+    MessageSendingStatus? status,
+    bool? skipPush,
   }) {
     assert(() {
       if (pinExpires is! DateTime &&
@@ -306,49 +329,47 @@ class Message extends Equatable {
       pinned: pinned ?? this.pinned,
       pinnedAt: pinnedAt ?? this.pinnedAt,
       pinnedBy: pinnedBy ?? this.pinnedBy,
-      pinExpires: pinExpires == _pinExpires ? this.pinExpires : pinExpires,
+      pinExpires:
+          pinExpires == _pinExpires ? this.pinExpires : pinExpires as DateTime?,
       skipPush: skipPush ?? this.skipPush,
     );
   }
 
   /// Returns a new [Message] that is a combination of this message and the
   /// given [other] message.
-  Message merge(Message other) {
-    if (other == null) return this;
-    return copyWith(
-      id: other.id,
-      text: other.text,
-      type: other.type,
-      attachments: other.attachments,
-      mentionedUsers: other.mentionedUsers,
-      reactionCounts: other.reactionCounts,
-      reactionScores: other.reactionScores,
-      latestReactions: other.latestReactions,
-      ownReactions: other.ownReactions,
-      parentId: other.parentId,
-      quotedMessage: other.quotedMessage,
-      quotedMessageId: other.quotedMessageId,
-      replyCount: other.replyCount,
-      threadParticipants: other.threadParticipants,
-      showInChannel: other.showInChannel,
-      command: other.command,
-      createdAt: other.createdAt,
-      silent: other.silent,
-      extraData: other.extraData,
-      user: other.user,
-      shadowed: other.shadowed,
-      updatedAt: other.updatedAt,
-      deletedAt: other.deletedAt,
-      status: other.status,
-      pinned: other.pinned,
-      pinnedAt: other.pinnedAt,
-      pinExpires: other.pinExpires,
-      pinnedBy: other.pinnedBy,
-    );
-  }
+  Message merge(Message other) => copyWith(
+        id: other.id,
+        text: other.text,
+        type: other.type,
+        attachments: other.attachments,
+        mentionedUsers: other.mentionedUsers,
+        reactionCounts: other.reactionCounts,
+        reactionScores: other.reactionScores,
+        latestReactions: other.latestReactions,
+        ownReactions: other.ownReactions,
+        parentId: other.parentId,
+        quotedMessage: other.quotedMessage,
+        quotedMessageId: other.quotedMessageId,
+        replyCount: other.replyCount,
+        threadParticipants: other.threadParticipants,
+        showInChannel: other.showInChannel,
+        command: other.command,
+        createdAt: other.createdAt,
+        silent: other.silent,
+        extraData: other.extraData,
+        user: other.user,
+        shadowed: other.shadowed,
+        updatedAt: other.updatedAt,
+        deletedAt: other.deletedAt,
+        status: other.status,
+        pinned: other.pinned,
+        pinnedAt: other.pinnedAt,
+        pinExpires: other.pinExpires,
+        pinnedBy: other.pinnedBy,
+      );
 
   @override
-  List<Object> get props => [
+  List<Object?> get props => [
         id,
         text,
         type,
@@ -386,7 +407,7 @@ class Message extends Equatable {
 @JsonSerializable()
 class TranslatedMessage extends Message {
   /// Constructor used for json serialization
-  TranslatedMessage(this.i18n);
+  TranslatedMessage(this.i18n) : super();
 
   /// Create a new instance from a json
   factory TranslatedMessage.fromJson(Map<String, dynamic> json) =>
@@ -395,7 +416,7 @@ class TranslatedMessage extends Message {
       );
 
   /// A Map of
-  final Map<String, String> i18n;
+  final Map<String, String>? i18n;
 
   /// Known top level fields.
   /// Useful for [Serialization] methods.
@@ -408,6 +429,5 @@ class TranslatedMessage extends Message {
   @override
   Map<String, dynamic> toJson() => Serialization.moveFromExtraDataToRoot(
         _$TranslatedMessageToJson(this),
-        topLevelFields,
       );
 }
diff --git a/packages/stream_chat/lib/src/models/message.g.dart b/packages/stream_chat/lib/src/models/message.g.dart
index 80df1589..ca094a83 100644
--- a/packages/stream_chat/lib/src/models/message.g.dart
+++ b/packages/stream_chat/lib/src/models/message.g.dart
@@ -6,64 +6,44 @@ part of 'message.dart';
 // JsonSerializableGenerator
 // **************************************************************************
 
-Message _$MessageFromJson(Map json) {
+Message _$MessageFromJson(Map<String, dynamic> json) {
   return Message(
-    id: json['id'] as String,
-    text: json['text'] as String,
-    type: json['type'] as String,
-    attachments: (json['attachments'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Attachment.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList(),
-    mentionedUsers: (json['mentioned_users'] as List)
-        ?.map((e) => e == null
-            ? null
-            : User.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList(),
-    silent: json['silent'] as bool,
-    shadowed: json['shadowed'] as bool,
-    reactionCounts: (json['reaction_counts'] as Map)?.map(
-      (k, e) => MapEntry(k as String, e as int),
+    id: json['id'] as String?,
+    text: json['text'] as String?,
+    type: json['type'] as String? ?? 'regular',
+    attachments: (json['attachments'] as List<dynamic>?)
+            ?.map((e) => Attachment.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [],
+    mentionedUsers: (json['mentioned_users'] as List<dynamic>?)
+            ?.map((e) => User.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [],
+    silent: json['silent'] as bool? ?? false,
+    shadowed: json['shadowed'] as bool? ?? false,
+    reactionCounts: (json['reaction_counts'] as Map<String, dynamic>?)?.map(
+      (k, e) => MapEntry(k, e as int),
     ),
-    reactionScores: (json['reaction_scores'] as Map)?.map(
-      (k, e) => MapEntry(k as String, e as int),
+    reactionScores: (json['reaction_scores'] as Map<String, dynamic>?)?.map(
+      (k, e) => MapEntry(k, e as int),
     ),
-    latestReactions: (json['latest_reactions'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Reaction.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList(),
-    ownReactions: (json['own_reactions'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Reaction.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList(),
-    parentId: json['parent_id'] as String,
+    latestReactions: (json['latest_reactions'] as List<dynamic>?)
+        ?.map((e) => Reaction.fromJson(e as Map<String, dynamic>))
+        .toList(),
+    ownReactions: (json['own_reactions'] as List<dynamic>?)
+        ?.map((e) => Reaction.fromJson(e as Map<String, dynamic>))
+        .toList(),
+    parentId: json['parent_id'] as String?,
     quotedMessage: json['quoted_message'] == null
         ? null
-        : Message.fromJson((json['quoted_message'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
-    quotedMessageId: json['quoted_message_id'] as String,
-    replyCount: json['reply_count'] as int,
-    threadParticipants: (json['thread_participants'] as List)
-        ?.map((e) => e == null
-            ? null
-            : User.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList(),
-    showInChannel: json['show_in_channel'] as bool,
-    command: json['command'] as String,
+        : Message.fromJson(json['quoted_message'] as Map<String, dynamic>),
+    quotedMessageId: json['quoted_message_id'] as String?,
+    replyCount: json['reply_count'] as int?,
+    threadParticipants: (json['thread_participants'] as List<dynamic>?)
+        ?.map((e) => User.fromJson(e as Map<String, dynamic>))
+        .toList(),
+    showInChannel: json['show_in_channel'] as bool?,
+    command: json['command'] as String?,
     createdAt: json['created_at'] == null
         ? null
         : DateTime.parse(json['created_at'] as String),
@@ -72,10 +52,8 @@ Message _$MessageFromJson(Map json) {
         : DateTime.parse(json['updated_at'] as String),
     user: json['user'] == null
         ? null
-        : User.fromJson((json['user'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
-    pinned: json['pinned'] as bool,
+        : User.fromJson(json['user'] as Map<String, dynamic>),
+    pinned: json['pinned'] as bool? ?? false,
     pinnedAt: json['pinned_at'] == null
         ? null
         : DateTime.parse(json['pinned_at'] as String),
@@ -84,16 +62,12 @@ Message _$MessageFromJson(Map json) {
         : DateTime.parse(json['pin_expires'] as String),
     pinnedBy: json['pinned_by'] == null
         ? null
-        : User.fromJson((json['pinned_by'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
-    extraData: (json['extra_data'] as Map)?.map(
-      (k, e) => MapEntry(k as String, e),
-    ),
+        : User.fromJson(json['pinned_by'] as Map<String, dynamic>),
+    extraData: json['extra_data'] as Map<String, dynamic>? ?? {},
     deletedAt: json['deleted_at'] == null
         ? null
         : DateTime.parse(json['deleted_at'] as String),
-    skipPush: json['skip_push'] as bool,
+    skipPush: json['skip_push'] as bool? ?? false,
   );
 }
 
@@ -110,8 +84,7 @@ Map<String, dynamic> _$MessageToJson(Message instance) {
   }
 
   writeNotNull('type', readonly(instance.type));
-  writeNotNull(
-      'attachments', instance.attachments?.map((e) => e?.toJson())?.toList());
+  val['attachments'] = instance.attachments.map((e) => e.toJson()).toList();
   val['mentioned_users'] = Serialization.userIds(instance.mentionedUsers);
   writeNotNull('reaction_counts', readonly(instance.reactionCounts));
   writeNotNull('reaction_scores', readonly(instance.reactionScores));
@@ -134,15 +107,15 @@ Map<String, dynamic> _$MessageToJson(Message instance) {
   val['pinned_at'] = readonly(instance.pinnedAt);
   val['pin_expires'] = instance.pinExpires?.toIso8601String();
   val['pinned_by'] = readonly(instance.pinnedBy);
-  writeNotNull('extra_data', instance.extraData);
+  val['extra_data'] = instance.extraData;
   writeNotNull('deleted_at', readonly(instance.deletedAt));
   return val;
 }
 
-TranslatedMessage _$TranslatedMessageFromJson(Map json) {
+TranslatedMessage _$TranslatedMessageFromJson(Map<String, dynamic> json) {
   return TranslatedMessage(
-    (json['i18n'] as Map)?.map(
-      (k, e) => MapEntry(k as String, e as String),
+    (json['i18n'] as Map<String, dynamic>?)?.map(
+      (k, e) => MapEntry(k, e as String),
     ),
   );
 }
diff --git a/packages/stream_chat/lib/src/models/mute.dart b/packages/stream_chat/lib/src/models/mute.dart
index e3d5e1a0..3ba26230 100644
--- a/packages/stream_chat/lib/src/models/mute.dart
+++ b/packages/stream_chat/lib/src/models/mute.dart
@@ -9,7 +9,12 @@ part 'mute.g.dart';
 @JsonSerializable()
 class Mute {
   /// Constructor used for json serialization
-  Mute({this.user, this.channel, this.createdAt, this.updatedAt});
+  Mute({
+    required this.user,
+    required this.channel,
+    required this.createdAt,
+    required this.updatedAt,
+  });
 
   /// Create a new instance from a json
   factory Mute.fromJson(Map<String, dynamic> json) => _$MuteFromJson(json);
diff --git a/packages/stream_chat/lib/src/models/mute.g.dart b/packages/stream_chat/lib/src/models/mute.g.dart
index 9d0b9318..e77b8707 100644
--- a/packages/stream_chat/lib/src/models/mute.g.dart
+++ b/packages/stream_chat/lib/src/models/mute.g.dart
@@ -6,24 +6,12 @@ part of 'mute.dart';
 // JsonSerializableGenerator
 // **************************************************************************
 
-Mute _$MuteFromJson(Map json) {
+Mute _$MuteFromJson(Map<String, dynamic> json) {
   return Mute(
-    user: json['user'] == null
-        ? null
-        : User.fromJson((json['user'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
-    channel: json['channel'] == null
-        ? null
-        : ChannelModel.fromJson((json['channel'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
-    createdAt: json['created_at'] == null
-        ? null
-        : DateTime.parse(json['created_at'] as String),
-    updatedAt: json['updated_at'] == null
-        ? null
-        : DateTime.parse(json['updated_at'] as String),
+    user: User.fromJson(json['user'] as Map<String, dynamic>),
+    channel: ChannelModel.fromJson(json['channel'] as Map<String, dynamic>),
+    createdAt: DateTime.parse(json['created_at'] as String),
+    updatedAt: DateTime.parse(json['updated_at'] as String),
   );
 }
 
diff --git a/packages/stream_chat/lib/src/models/own_user.dart b/packages/stream_chat/lib/src/models/own_user.dart
index 18ee2abf..3ce951cf 100644
--- a/packages/stream_chat/lib/src/models/own_user.dart
+++ b/packages/stream_chat/lib/src/models/own_user.dart
@@ -12,19 +12,19 @@ part 'own_user.g.dart';
 class OwnUser extends User {
   /// Constructor used for json serialization
   OwnUser({
-    this.devices,
-    this.mutes,
-    this.totalUnreadCount,
+    this.devices = const [],
+    this.mutes = const [],
+    this.totalUnreadCount = 0,
     this.unreadChannels,
-    this.channelMutes,
-    String id,
-    String role,
-    DateTime createdAt,
-    DateTime updatedAt,
-    DateTime lastActive,
-    bool online,
-    Map<String, dynamic> extraData,
-    bool banned,
+    this.channelMutes = const [],
+    String id = '',
+    String role = '',
+    DateTime? createdAt,
+    DateTime? updatedAt,
+    DateTime? lastActive,
+    bool online = false,
+    Map<String, dynamic> extraData = const {},
+    bool banned = false,
   }) : super(
           id: id,
           role: role,
@@ -41,24 +41,34 @@ class OwnUser extends User {
       Serialization.moveToExtraDataFromRoot(json, topLevelFields));
 
   /// List of user devices
-  @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
+  @JsonKey(
+      includeIfNull: false,
+      toJson: Serialization.readOnly,
+      defaultValue: <Device>[])
   final List<Device> devices;
 
   /// List of users muted by the user
-  @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
+  @JsonKey(
+      includeIfNull: false,
+      toJson: Serialization.readOnly,
+      defaultValue: <Mute>[])
   final List<Mute> mutes;
 
   /// List of users muted by the user
-  @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
+  @JsonKey(
+      includeIfNull: false,
+      toJson: Serialization.readOnly,
+      defaultValue: <Mute>[])
   final List<Mute> channelMutes;
 
   /// Total unread messages by the user
-  @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
+  @JsonKey(
+      includeIfNull: false, toJson: Serialization.readOnly, defaultValue: 0)
   final int totalUnreadCount;
 
   /// Total unread channels by the user
   @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
-  final int unreadChannels;
+  final int? unreadChannels;
 
   /// Known top level fields.
   /// Useful for [Serialization] methods.
@@ -74,5 +84,6 @@ class OwnUser extends User {
   /// Serialize to json
   @override
   Map<String, dynamic> toJson() => Serialization.moveFromExtraDataToRoot(
-      _$OwnUserToJson(this), topLevelFields);
+        _$OwnUserToJson(this),
+      );
 }
diff --git a/packages/stream_chat/lib/src/models/own_user.g.dart b/packages/stream_chat/lib/src/models/own_user.g.dart
index 887e6b28..5802060c 100644
--- a/packages/stream_chat/lib/src/models/own_user.g.dart
+++ b/packages/stream_chat/lib/src/models/own_user.g.dart
@@ -6,33 +6,24 @@ part of 'own_user.dart';
 // JsonSerializableGenerator
 // **************************************************************************
 
-OwnUser _$OwnUserFromJson(Map json) {
+OwnUser _$OwnUserFromJson(Map<String, dynamic> json) {
   return OwnUser(
-    devices: (json['devices'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Device.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList(),
-    mutes: (json['mutes'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Mute.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList(),
-    totalUnreadCount: json['total_unread_count'] as int,
-    unreadChannels: json['unread_channels'] as int,
-    channelMutes: (json['channel_mutes'] as List)
-        ?.map((e) => e == null
-            ? null
-            : Mute.fromJson((e as Map)?.map(
-                (k, e) => MapEntry(k as String, e),
-              )))
-        ?.toList(),
+    devices: (json['devices'] as List<dynamic>?)
+            ?.map((e) => Device.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [],
+    mutes: (json['mutes'] as List<dynamic>?)
+            ?.map((e) => Mute.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [],
+    totalUnreadCount: json['total_unread_count'] as int? ?? 0,
+    unreadChannels: json['unread_channels'] as int?,
+    channelMutes: (json['channel_mutes'] as List<dynamic>?)
+            ?.map((e) => Mute.fromJson(e as Map<String, dynamic>))
+            .toList() ??
+        [],
     id: json['id'] as String,
-    role: json['role'] as String,
+    role: json['role'] as String? ?? '',
     createdAt: json['created_at'] == null
         ? null
         : DateTime.parse(json['created_at'] as String),
@@ -42,11 +33,9 @@ OwnUser _$OwnUserFromJson(Map json) {
     lastActive: json['last_active'] == null
         ? null
         : DateTime.parse(json['last_active'] as String),
-    online: json['online'] as bool,
-    extraData: (json['extra_data'] as Map)?.map(
-      (k, e) => MapEntry(k as String, e),
-    ),
-    banned: json['banned'] as bool,
+    online: json['online'] as bool? ?? false,
+    extraData: json['extra_data'] as Map<String, dynamic>,
+    banned: json['banned'] as bool? ?? false,
   );
 }
 
@@ -67,7 +56,7 @@ Map<String, dynamic> _$OwnUserToJson(OwnUser instance) {
   writeNotNull('last_active', readonly(instance.lastActive));
   writeNotNull('online', readonly(instance.online));
   writeNotNull('banned', readonly(instance.banned));
-  writeNotNull('extra_data', instance.extraData);
+  val['extra_data'] = instance.extraData;
   writeNotNull('devices', readonly(instance.devices));
   writeNotNull('mutes', readonly(instance.mutes));
   writeNotNull('channel_mutes', readonly(instance.channelMutes));
diff --git a/packages/stream_chat/lib/src/models/reaction.dart b/packages/stream_chat/lib/src/models/reaction.dart
index 6792bf3f..82913218 100644
--- a/packages/stream_chat/lib/src/models/reaction.dart
+++ b/packages/stream_chat/lib/src/models/reaction.dart
@@ -10,20 +10,24 @@ class Reaction {
   /// Constructor used for json serialization
   Reaction({
     this.messageId,
-    this.createdAt,
-    this.type,
+    DateTime? createdAt,
+    required this.type,
     this.user,
-    String userId,
-    this.score,
+    String? userId,
+    this.score = 0,
     this.extraData,
-  }) : userId = userId ?? user?.id;
+  })  : userId = userId ?? user?.id,
+        createdAt = createdAt ?? DateTime.now();
 
   /// Create a new instance from a json
-  factory Reaction.fromJson(Map<String, dynamic> json) => _$ReactionFromJson(
-      Serialization.moveToExtraDataFromRoot(json, topLevelFields));
+  factory Reaction.fromJson(Map<String, dynamic> json) =>
+      _$ReactionFromJson(Serialization.moveToExtraDataFromRoot(
+        json,
+        topLevelFields,
+      ));
 
   /// The messageId to which the reaction belongs
-  final String messageId;
+  final String? messageId;
 
   /// The type of the reaction
   final String type;
@@ -34,18 +38,19 @@ class Reaction {
 
   /// The user that sent the reaction
   @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
-  final User user;
+  final User? user;
 
   /// The score of the reaction (ie. number of reactions sent)
+  @JsonKey(defaultValue: 0)
   final int score;
 
   /// The userId that sent the reaction
   @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
-  final String userId;
+  final String? userId;
 
   /// Reaction custom extraData
   @JsonKey(includeIfNull: false)
-  final Map<String, dynamic> extraData;
+  final Map<String, dynamic>? extraData;
 
   /// Map of custom user extraData
   static const topLevelFields = [
@@ -59,17 +64,18 @@ class Reaction {
 
   /// Serialize to json
   Map<String, dynamic> toJson() => Serialization.moveFromExtraDataToRoot(
-      _$ReactionToJson(this), topLevelFields);
+        _$ReactionToJson(this),
+      );
 
   /// Creates a copy of [Reaction] with specified attributes overridden.
   Reaction copyWith({
-    String messageId,
-    DateTime createdAt,
-    String type,
-    User user,
-    String userId,
-    int score,
-    Map<String, dynamic> extraData,
+    String? messageId,
+    DateTime? createdAt,
+    String? type,
+    User? user,
+    String? userId,
+    int? score,
+    Map<String, dynamic>? extraData,
   }) =>
       Reaction(
         messageId: messageId ?? this.messageId,
@@ -83,16 +89,13 @@ class Reaction {
 
   /// Returns a new [Reaction] that is a combination of this reaction and the
   /// given [other] reaction.
-  Reaction merge(Reaction other) {
-    if (other == null) return this;
-    return copyWith(
-      messageId: other.messageId,
-      createdAt: other.createdAt,
-      type: other.type,
-      user: other.user,
-      userId: other.userId,
-      score: other.score,
-      extraData: other.extraData,
-    );
-  }
+  Reaction merge(Reaction other) => copyWith(
+        messageId: other.messageId,
+        createdAt: other.createdAt,
+        type: other.type,
+        user: other.user,
+        userId: other.userId,
+        score: other.score,
+        extraData: other.extraData,
+      );
 }
diff --git a/packages/stream_chat/lib/src/models/reaction.g.dart b/packages/stream_chat/lib/src/models/reaction.g.dart
index a270af01..963b4d21 100644
--- a/packages/stream_chat/lib/src/models/reaction.g.dart
+++ b/packages/stream_chat/lib/src/models/reaction.g.dart
@@ -6,23 +6,19 @@ part of 'reaction.dart';
 // JsonSerializableGenerator
 // **************************************************************************
 
-Reaction _$ReactionFromJson(Map json) {
+Reaction _$ReactionFromJson(Map<String, dynamic> json) {
   return Reaction(
-    messageId: json['message_id'] as String,
+    messageId: json['message_id'] as String?,
     createdAt: json['created_at'] == null
         ? null
         : DateTime.parse(json['created_at'] as String),
     type: json['type'] as String,
     user: json['user'] == null
         ? null
-        : User.fromJson((json['user'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
-    userId: json['user_id'] as String,
-    score: json['score'] as int,
-    extraData: (json['extra_data'] as Map)?.map(
-      (k, e) => MapEntry(k as String, e),
-    ),
+        : User.fromJson(json['user'] as Map<String, dynamic>),
+    userId: json['user_id'] as String?,
+    score: json['score'] as int? ?? 0,
+    extraData: json['extra_data'] as Map<String, dynamic>?,
   );
 }
 
diff --git a/packages/stream_chat/lib/src/models/read.dart b/packages/stream_chat/lib/src/models/read.dart
index fc8ef1bc..cbd47dd1 100644
--- a/packages/stream_chat/lib/src/models/read.dart
+++ b/packages/stream_chat/lib/src/models/read.dart
@@ -8,9 +8,9 @@ part 'read.g.dart';
 class Read {
   /// Constructor used for json serialization
   Read({
-    this.lastRead,
-    this.user,
-    this.unreadMessages,
+    required this.lastRead,
+    required this.user,
+    this.unreadMessages = 0,
   });
 
   /// Create a new instance from a json
@@ -23,6 +23,7 @@ class Read {
   final User user;
 
   /// Number of unread messages
+  @JsonKey(defaultValue: 0)
   final int unreadMessages;
 
   /// Serialize to json
@@ -30,9 +31,9 @@ class Read {
 
   /// Creates a copy of [Read] with specified attributes overridden.
   Read copyWith({
-    DateTime lastRead,
-    User user,
-    int unreadMessages,
+    DateTime? lastRead,
+    User? user,
+    int? unreadMessages,
   }) =>
       Read(
         lastRead: lastRead ?? this.lastRead,
diff --git a/packages/stream_chat/lib/src/models/read.g.dart b/packages/stream_chat/lib/src/models/read.g.dart
index d04ae146..93c832d8 100644
--- a/packages/stream_chat/lib/src/models/read.g.dart
+++ b/packages/stream_chat/lib/src/models/read.g.dart
@@ -6,22 +6,16 @@ part of 'read.dart';
 // JsonSerializableGenerator
 // **************************************************************************
 
-Read _$ReadFromJson(Map json) {
+Read _$ReadFromJson(Map<String, dynamic> json) {
   return Read(
-    lastRead: json['last_read'] == null
-        ? null
-        : DateTime.parse(json['last_read'] as String),
-    user: json['user'] == null
-        ? null
-        : User.fromJson((json['user'] as Map)?.map(
-            (k, e) => MapEntry(k as String, e),
-          )),
-    unreadMessages: json['unread_messages'] as int,
+    lastRead: DateTime.parse(json['last_read'] as String),
+    user: User.fromJson(json['user'] as Map<String, dynamic>),
+    unreadMessages: json['unread_messages'] as int? ?? 0,
   );
 }
 
 Map<String, dynamic> _$ReadToJson(Read instance) => <String, dynamic>{
-      'last_read': instance.lastRead?.toIso8601String(),
-      'user': instance.user?.toJson(),
+      'last_read': instance.lastRead.toIso8601String(),
+      'user': instance.user.toJson(),
       'unread_messages': instance.unreadMessages,
     };
diff --git a/packages/stream_chat/lib/src/models/serialization.dart b/packages/stream_chat/lib/src/models/serialization.dart
index 18cdd545..d584912e 100644
--- a/packages/stream_chat/lib/src/models/serialization.dart
+++ b/packages/stream_chat/lib/src/models/serialization.dart
@@ -10,16 +10,14 @@ class Serialization {
   static const Function readOnly = readonly;
 
   /// List of users to list of userIds
-  static List<String> userIds(List<User> users) =>
-      users?.map((u) => u.id)?.toList();
+  static List<String>? userIds(List<User>? users) =>
+      users?.map((u) => u.id).toList();
 
   /// Takes unknown json keys and puts them in the `extra_data` key
   static Map<String, dynamic> moveToExtraDataFromRoot(
     Map<String, dynamic> json,
     List<String> topLevelFields,
   ) {
-    if (json == null) return null;
-
     final jsonClone = Map<String, dynamic>.from(json);
 
     final extraDataMap = Map<String, dynamic>.from(json)
@@ -38,7 +36,6 @@ class Serialization {
   /// the json map
   static Map<String, dynamic> moveFromExtraDataToRoot(
     Map<String, dynamic> json,
-    List<String> topLevelFields,
   ) {
     final jsonClone = Map<String, dynamic>.from(json);
     return jsonClone
diff --git a/packages/stream_chat/lib/src/models/user.dart b/packages/stream_chat/lib/src/models/user.dart
index 3b9f9add..67fc99f0 100644
--- a/packages/stream_chat/lib/src/models/user.dart
+++ b/packages/stream_chat/lib/src/models/user.dart
@@ -8,16 +8,17 @@ part 'user.g.dart';
 class User {
   /// Constructor used for json serialization
   User({
-    this.id,
-    this.role,
-    this.createdAt,
-    this.updatedAt,
+    this.id = '',
+    this.role = '',
+    DateTime? createdAt,
+    DateTime? updatedAt,
     this.lastActive,
-    this.online,
-    this.extraData,
-    this.banned,
-    this.teams,
-  });
+    this.online = false,
+    this.extraData = const {},
+    this.banned = false,
+    this.teams = const [],
+  })  : createdAt = createdAt ?? DateTime.now(),
+        updatedAt = updatedAt ?? DateTime.now();
 
   /// Create a new instance from a json
   factory User.fromJson(Map<String, dynamic> json) => _$UserFromJson(
@@ -26,14 +27,14 @@ class User {
   /// Use this named constructor to create a new user instance
   User.init(
     this.id, {
-    this.online,
-    this.extraData,
-  })  : createdAt = null,
-        updatedAt = null,
-        lastActive = null,
-        banned = null,
-        teams = null,
-        role = null;
+    this.online = false,
+    this.extraData = const {},
+    required this.createdAt,
+    required this.updatedAt,
+    this.teams = const [],
+    required this.role,
+  })   : lastActive = null,
+        banned = false;
 
   /// Known top level fields.
   /// Useful for [Serialization] methods.
@@ -52,11 +53,15 @@ class User {
   final String id;
 
   /// User role
-  @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
+  @JsonKey(
+      includeIfNull: false, toJson: Serialization.readOnly, defaultValue: '')
   final String role;
 
   /// User role
-  @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
+  @JsonKey(
+      includeIfNull: false,
+      toJson: Serialization.readOnly,
+      defaultValue: <String>[])
   final List<String> teams;
 
   /// Date of user creation
@@ -69,14 +74,16 @@ class User {
 
   /// Date of last user connection
   @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
-  final DateTime lastActive;
+  final DateTime? lastActive;
 
   /// True if user is online
-  @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
+  @JsonKey(
+      includeIfNull: false, toJson: Serialization.readOnly, defaultValue: false)
   final bool online;
 
   /// True if user is banned from the chat
-  @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
+  @JsonKey(
+      includeIfNull: false, toJson: Serialization.readOnly, defaultValue: false)
   final bool banned;
 
   /// Map of custom user extraData
@@ -87,8 +94,8 @@ class User {
   int get hashCode => id.hashCode;
 
   /// Shortcut for user name
-  String get name =>
-      (extraData?.containsKey('name') == true && extraData['name'] != '')
+  String? get name =>
+      (extraData.containsKey('name') == true && extraData['name'] != '')
           ? extraData['name']
           : id;
 
@@ -98,20 +105,21 @@ class User {
       other is User && runtimeType == other.runtimeType && id == other.id;
 
   /// Serialize to json
-  Map<String, dynamic> toJson() =>
-      Serialization.moveFromExtraDataToRoot(_$UserToJson(this), topLevelFields);
+  Map<String, dynamic> toJson() => Serialization.moveFromExtraDataToRoot(
+        _$UserToJson(this),
+      );
 
   /// Creates a copy of [User] with specified attributes overridden.
   User copyWith({
-    String id,
-    String role,
-    DateTime createdAt,
-    DateTime updatedAt,
-    DateTime lastActive,
-    bool online,
-    Map<String, dynamic> extraData,
-    bool banned,
-    List<String> teams,
+    String? id,
+    String? role,
+    DateTime? createdAt,
+    DateTime? updatedAt,
+    DateTime? lastActive,
+    bool? online,
+    Map<String, dynamic>? extraData,
+    bool? banned,
+    List<String>? teams,
   }) =>
       User(
         id: id ?? this.id,
diff --git a/packages/stream_chat/lib/src/models/user.g.dart b/packages/stream_chat/lib/src/models/user.g.dart
index b27935a7..18408d76 100644
--- a/packages/stream_chat/lib/src/models/user.g.dart
+++ b/packages/stream_chat/lib/src/models/user.g.dart
@@ -6,10 +6,10 @@ part of 'user.dart';
 // JsonSerializableGenerator
 // **************************************************************************
 
-User _$UserFromJson(Map json) {
+User _$UserFromJson(Map<String, dynamic> json) {
   return User(
     id: json['id'] as String,
-    role: json['role'] as String,
+    role: json['role'] as String? ?? '',
     createdAt: json['created_at'] == null
         ? null
         : DateTime.parse(json['created_at'] as String),
@@ -19,12 +19,12 @@ User _$UserFromJson(Map json) {
     lastActive: json['last_active'] == null
         ? null
         : DateTime.parse(json['last_active'] as String),
-    online: json['online'] as bool,
-    extraData: (json['extra_data'] as Map)?.map(
-      (k, e) => MapEntry(k as String, e),
-    ),
-    banned: json['banned'] as bool,
-    teams: (json['teams'] as List)?.map((e) => e as String)?.toList(),
+    online: json['online'] as bool? ?? false,
+    extraData: json['extra_data'] as Map<String, dynamic>,
+    banned: json['banned'] as bool? ?? false,
+    teams:
+        (json['teams'] as List<dynamic>?)?.map((e) => e as String).toList() ??
+            [],
   );
 }
 
@@ -46,6 +46,6 @@ Map<String, dynamic> _$UserToJson(User instance) {
   writeNotNull('last_active', readonly(instance.lastActive));
   writeNotNull('online', readonly(instance.online));
   writeNotNull('banned', readonly(instance.banned));
-  writeNotNull('extra_data', instance.extraData);
+  val['extra_data'] = instance.extraData;
   return val;
 }
diff --git a/packages/stream_chat/pubspec.yaml b/packages/stream_chat/pubspec.yaml
index f221fc39..8e0d5f12 100644
--- a/packages/stream_chat/pubspec.yaml
+++ b/packages/stream_chat/pubspec.yaml
@@ -6,26 +6,26 @@ repository: https://github.com/GetStream/stream-chat-flutter
 issue_tracker: https://github.com/GetStream/stream-chat-flutter/issues
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
+  sdk: '>=2.12.0 <3.0.0'
 
 dependencies:
   async: ^2.5.0
   collection: ^1.15.0
-  dio: ">=4.0.0-prev3 <4.0.0"
+  dio: ^4.0.0
   equatable: ^2.0.0
   freezed_annotation: ^0.14.0
   http_parser: ^4.0.0
-  json_annotation: ^4.0.0
-  logging: ^1.0.0
+  json_annotation: ^4.0.1
+  logging: ^1.0.1
   meta: ^1.3.0
   mime: ^1.0.0
   rxdart: ^0.26.0
-  uuid: ^3.0.0
+  uuid: ^3.0.4
   web_socket_channel: ^2.0.0
 
 dev_dependencies:
-  build_runner: ^1.10.0
-  freezed: ^0.14.0
-  json_serializable: ^4.0.0
-  mocktail: ^0.1.0
-  test: ^1.16.0
+  build_runner: ^1.12.2
+  freezed: ^0.14.1+2
+  json_serializable: ^4.1.0
+  mocktail: ^0.1.1
+  test: ^1.16.8
diff --git a/packages/stream_chat/test/src/api/channel_test.dart b/packages/stream_chat/test/src/api/channel_test.dart
index ae4d5296..041a3e49 100644
--- a/packages/stream_chat/test/src/api/channel_test.dart
+++ b/packages/stream_chat/test/src/api/channel_test.dart
@@ -1,3 +1,5 @@
+import 'dart:convert';
+
 import 'package:dio/dio.dart';
 import 'package:dio/native_imp.dart';
 import 'package:mocktail/mocktail.dart';
@@ -6,11 +8,10 @@ import 'package:stream_chat/src/client.dart';
 import 'package:stream_chat/src/event_type.dart';
 import 'package:stream_chat/src/models/event.dart';
 import 'package:stream_chat/src/models/message.dart';
-import 'package:stream_chat/src/models/reaction.dart';
 import 'package:stream_chat/src/models/own_user.dart';
-import 'package:test/test.dart';
-
+import 'package:stream_chat/src/models/reaction.dart';
 import 'package:stream_chat/stream_chat.dart';
+import 'package:test/test.dart';
 
 class MockDio extends Mock implements DioForNative {}
 
@@ -37,6 +38,17 @@ void main() {
         final channelClient = client.channel('messaging', id: 'testid');
         final message = Message(text: 'hey', id: 'test');
 
+        when(() => mockDio.post<String>(
+              any(),
+              data: any(named: 'data'),
+            )).thenAnswer((_) async => Response(
+              data: jsonEncode(ChannelState()),
+              statusCode: 200,
+              requestOptions: FakeRequestOptions(),
+            ));
+
+        await channelClient.watch();
+
         when(
           () => mockDio.post<String>(
             '/channels/messaging/testid/message',
@@ -44,7 +56,7 @@ void main() {
           ),
         ).thenAnswer(
           (_) async => Response(
-            data: '{}',
+            data: jsonEncode({'message': message}),
             statusCode: 200,
             requestOptions: FakeRequestOptions(),
           ),
@@ -76,7 +88,7 @@ void main() {
               any(),
               data: any(named: 'data'),
             )).thenAnswer((_) async => Response(
-              data: '{}',
+              data: jsonEncode(ChannelState()),
               statusCode: 200,
               requestOptions: FakeRequestOptions(),
             ));
@@ -226,6 +238,17 @@ void main() {
         );
         final channelClient = client.channel(channelType, id: channelId);
 
+        when(() => mockDio.post<String>(
+              any(),
+              data: any(named: 'data'),
+            )).thenAnswer((_) async => Response(
+              data: jsonEncode(ChannelState()),
+              statusCode: 200,
+              requestOptions: FakeRequestOptions(),
+            ));
+
+        await channelClient.watch();
+
         when(() => mockUploader.sendFile(file, channelId, channelType))
             .thenAnswer((_) async => SendFileResponse());
 
@@ -254,6 +277,17 @@ void main() {
         );
         final channelClient = client.channel(channelType, id: channelId);
 
+        when(() => mockDio.post<String>(
+              any(),
+              data: any(named: 'data'),
+            )).thenAnswer((_) async => Response(
+              data: jsonEncode(ChannelState()),
+              statusCode: 200,
+              requestOptions: FakeRequestOptions(),
+            ));
+
+        await channelClient.watch();
+
         when(() => mockUploader.sendImage(image, channelId, channelType))
             .thenAnswer((_) async => SendImageResponse());
 
@@ -277,6 +311,17 @@ void main() {
         final channelClient = client.channel('messaging', id: 'testid');
         const url = 'url';
 
+        when(() => mockDio.post<String>(
+              any(),
+              data: any(named: 'data'),
+            )).thenAnswer((_) async => Response(
+              data: jsonEncode(ChannelState()),
+              statusCode: 200,
+              requestOptions: FakeRequestOptions(),
+            ));
+
+        await channelClient.watch();
+
         when(
           () => mockDio.delete<String>(
             '/channels/messaging/testid/file',
@@ -310,6 +355,17 @@ void main() {
         final channelClient = client.channel('messaging', id: 'testid');
         const url = 'url';
 
+        when(() => mockDio.post<String>(
+              any(),
+              data: any(named: 'data'),
+            )).thenAnswer((_) async => Response(
+              data: jsonEncode(ChannelState()),
+              statusCode: 200,
+              requestOptions: FakeRequestOptions(),
+            ));
+
+        await channelClient.watch();
+
         when(
           () => mockDio.delete<String>(
             '/channels/messaging/testid/image',
@@ -356,6 +412,17 @@ void main() {
         final channelClient = client.channel('messaging', id: 'testid');
         final message = Message(text: 'Hello', id: 'test');
 
+        when(() => mockDio.post<String>(
+              any(),
+              data: any(named: 'data'),
+            )).thenAnswer((_) async => Response(
+              data: jsonEncode(ChannelState()),
+              statusCode: 200,
+              requestOptions: FakeRequestOptions(),
+            ));
+
+        await channelClient.watch();
+
         when(
           () => mockDio.post<String>(
             '/messages/${message.id}',
@@ -363,7 +430,7 @@ void main() {
           ),
         ).thenAnswer(
           (_) async => Response(
-            data: '{}',
+            data: jsonEncode({'message': message}),
             statusCode: 200,
             requestOptions: FakeRequestOptions(),
           ),
@@ -390,6 +457,17 @@ void main() {
         final channelClient = client.channel('messaging', id: 'testid');
         final message = Message(text: 'Hello', id: 'test');
 
+        when(() => mockDio.post<String>(
+              any(),
+              data: any(named: 'data'),
+            )).thenAnswer((_) async => Response(
+              data: jsonEncode(ChannelState()),
+              statusCode: 200,
+              requestOptions: FakeRequestOptions(),
+            ));
+
+        await channelClient.watch();
+
         when(
           () => mockDio.post<String>(
             '/messages/${message.id}',
@@ -397,7 +475,7 @@ void main() {
           ),
         ).thenAnswer(
           (_) async => Response(
-            data: '{}',
+            data: jsonEncode({'message': message}),
             statusCode: 200,
             requestOptions: FakeRequestOptions(),
           ),
@@ -564,14 +642,32 @@ void main() {
           'api-key',
           httpClient: mockDio,
           tokenProvider: (_) async => '',
-        )..state.user = OwnUser(id: 'test-id');
+        );
 
-        final channelClient = client.channel('messaging', id: 'testid');
+        final user = OwnUser(id: 'test-id');
+
+        client.state.user = user;
+
+        final message = Message(id: 'messageid');
         const reactionType = 'test';
+        final reaction = Reaction(type: reactionType);
+        final channelClient = client.channel('messaging', id: 'testid');
+
+        when(() => mockDio.post<String>(
+              any(),
+              data: any(named: 'data'),
+            )).thenAnswer(
+          (_) async => Response(
+            data: '{}',
+            statusCode: 200,
+            requestOptions: FakeRequestOptions(),
+          ),
+        );
+        await channelClient.watch();
 
         when(
           () => mockDio.post<String>(
-            '/messages/messageid/reaction',
+            '/messages/${message.id}/reaction',
             data: {
               'reaction': {
                 'type': reactionType,
@@ -581,20 +677,17 @@ void main() {
           ),
         ).thenAnswer(
           (_) async => Response(
-            data: '{}',
+            data: jsonEncode({
+              'message': message,
+              'reaction': reaction,
+            }),
             statusCode: 200,
             requestOptions: FakeRequestOptions(),
           ),
         );
 
         await channelClient.sendReaction(
-          Message(
-            id: 'messageid',
-            reactionCounts: const <String, int>{},
-            reactionScores: const <String, int>{},
-            latestReactions: const <Reaction>[],
-            ownReactions: const <Reaction>[],
-          ),
+          message,
           reactionType,
         );
 
@@ -617,7 +710,9 @@ void main() {
           'api-key',
           httpClient: mockDio,
           tokenProvider: (_) async => '',
-        )..state.user = OwnUser(id: 'test-id');
+        );
+
+        client.state.user = OwnUser(id: 'test-id');
 
         final channelClient = client.channel('messaging', id: 'testid');
 
@@ -634,12 +729,14 @@ void main() {
         await channelClient.deleteReaction(
           Message(
             id: 'messageid',
-            reactionCounts: const <String, int>{},
-            reactionScores: const <String, int>{},
-            latestReactions: const <Reaction>[],
-            ownReactions: const <Reaction>[],
           ),
-          Reaction(type: 'test'),
+          Reaction(
+            type: 'test',
+            createdAt: DateTime.now(),
+            user: User(
+              id: client.state.user?.id ?? '',
+            ),
+          ),
         );
 
         verify(() =>
@@ -694,26 +791,44 @@ void main() {
           tokenProvider: (_) async => '',
         );
         final channelClient = client.channel('messaging', id: 'testid');
-        final members = ['vishal'];
+        final channelModel = ChannelModel(cid: 'messaging:testid');
+
+        when(() => mockDio.post<String>(
+              any(),
+              data: any(named: 'data'),
+            )).thenAnswer((_) async => Response(
+              data: jsonEncode(ChannelState(channel: channelModel)),
+              statusCode: 200,
+              requestOptions: FakeRequestOptions(),
+            ));
+
+        await channelClient.watch();
+
+        final members = [Member(userId: 'vishal')];
+        final memberIds = members.map((e) => e.userId!).toList();
         final message = Message(text: 'test');
 
         when(
           () => mockDio.post<String>(
             '/channels/messaging/testid',
-            data: {'add_members': members, 'message': message.toJson()},
+            data: {'add_members': memberIds, 'message': message.toJson()},
           ),
         ).thenAnswer(
           (_) async => Response(
-            data: '{}',
+            data: jsonEncode({
+              'members': members,
+              'message': message,
+              'channel': channelModel,
+            }),
             statusCode: 200,
             requestOptions: FakeRequestOptions(),
           ),
         );
 
-        await channelClient.addMembers(members, message);
+        await channelClient.addMembers(memberIds, message);
 
         verify(() => mockDio.post<String>('/channels/messaging/testid',
-                data: {'add_members': members, 'message': message.toJson()}))
+                data: {'add_members': memberIds, 'message': message.toJson()}))
             .called(1);
       });
 
@@ -729,6 +844,19 @@ void main() {
           tokenProvider: (_) async => '',
         );
         final channelClient = client.channel('messaging', id: 'testid');
+        final channelModel = ChannelModel(cid: 'messaging:testid');
+
+        when(() => mockDio.post<String>(
+              any(),
+              data: any(named: 'data'),
+            )).thenAnswer((_) async => Response(
+              data: jsonEncode(ChannelState(channel: channelModel)),
+              statusCode: 200,
+              requestOptions: FakeRequestOptions(),
+            ));
+
+        await channelClient.watch();
+
         final message = Message(text: 'test');
 
         when(
@@ -738,7 +866,10 @@ void main() {
           ),
         ).thenAnswer(
           (_) async => Response(
-            data: '{}',
+            data: jsonEncode({
+              'message': message,
+              'channel': channelModel,
+            }),
             statusCode: 200,
             requestOptions: FakeRequestOptions(),
           ),
@@ -1069,8 +1200,8 @@ void main() {
 
           verify(() => mockDio.post<String>('/channels/messaging/query',
               data: options)).called(1);
-          expect(channelClient.id, response.channel.id);
-          expect(channelClient.cid, response.channel.cid);
+          expect(channelClient.id, response.channel?.id);
+          expect(channelClient.cid, response.channel?.cid);
         });
 
         test('with id', () async {
@@ -1706,8 +1837,8 @@ void main() {
 
         verify(() => mockDio.post<String>('/channels/messaging/query',
             data: options)).called(1);
-        expect(channelClient.id, response.channel.id);
-        expect(channelClient.cid, response.channel.cid);
+        expect(channelClient.id, response.channel?.id);
+        expect(channelClient.cid, response.channel?.cid);
       });
 
       test('watch', () async {
@@ -2027,8 +2158,8 @@ void main() {
 
         verify(() => mockDio.post<String>('/channels/messaging/query',
             data: options)).called(1);
-        expect(channelClient.id, response.channel.id);
-        expect(channelClient.cid, response.channel.cid);
+        expect(channelClient.id, response.channel?.id);
+        expect(channelClient.cid, response.channel?.cid);
       });
 
       test('stopWatching', () async {
@@ -2077,6 +2208,19 @@ void main() {
           tokenProvider: (_) async => '',
         );
         final channelClient = client.channel('messaging', id: 'testid');
+        final channelModel = ChannelModel(cid: 'messaging:testid');
+
+        when(() => mockDio.post<String>(
+              any(),
+              data: any(named: 'data'),
+            )).thenAnswer((_) async => Response(
+              data: jsonEncode(ChannelState(channel: channelModel)),
+              statusCode: 200,
+              requestOptions: FakeRequestOptions(),
+            ));
+
+        await channelClient.watch();
+
         final message = Message(text: 'test');
 
         when(
@@ -2089,7 +2233,10 @@ void main() {
           ),
         ).thenAnswer(
           (_) async => Response(
-            data: '{}',
+            data: jsonEncode({
+              'channel': channelModel,
+              'message': message,
+            }),
             statusCode: 200,
             requestOptions: FakeRequestOptions(),
           ),
@@ -2176,6 +2323,19 @@ void main() {
           tokenProvider: (_) async => '',
         );
         final channelClient = client.channel('messaging', id: 'testid');
+        final channelModel = ChannelModel(cid: 'messaging:testid');
+
+        when(() => mockDio.post<String>(
+              any(),
+              data: any(named: 'data'),
+            )).thenAnswer((_) async => Response(
+              data: jsonEncode(ChannelState(channel: channelModel)),
+              statusCode: 200,
+              requestOptions: FakeRequestOptions(),
+            ));
+
+        await channelClient.watch();
+
         final message = Message(text: 'test');
 
         when(
@@ -2185,7 +2345,10 @@ void main() {
           ),
         ).thenAnswer(
           (_) async => Response(
-            data: '{}',
+            data: jsonEncode({
+              'message': message,
+              'channel': channelModel,
+            }),
             statusCode: 200,
             requestOptions: FakeRequestOptions(),
           ),
@@ -2210,26 +2373,45 @@ void main() {
           tokenProvider: (_) async => '',
         );
         final channelClient = client.channel('messaging', id: 'testid');
-        final members = ['vishal'];
+        final channelModel = ChannelModel(cid: 'messaging:testid');
+
+        when(() => mockDio.post<String>(
+              any(),
+              data: any(named: 'data'),
+            )).thenAnswer((_) async => Response(
+              data: jsonEncode(ChannelState(channel: channelModel)),
+              statusCode: 200,
+              requestOptions: FakeRequestOptions(),
+            ));
+
+        await channelClient.watch();
+
+        final members = [Member(userId: 'vishal')];
+        final memberIds = members.map((e) => e.userId!).toList();
         final message = Message(text: 'test');
 
         when(
           () => mockDio.post<String>(
             '/channels/messaging/testid',
-            data: {'invites': members, 'message': message.toJson()},
+            data: {'invites': memberIds, 'message': message.toJson()},
           ),
         ).thenAnswer(
           (_) async => Response(
-            data: '{}',
+            data: jsonEncode({
+              'members': members,
+              'message': message,
+              'channel': channelModel,
+            }),
             statusCode: 200,
             requestOptions: FakeRequestOptions(),
           ),
         );
 
-        await channelClient.inviteMembers(members, message);
+        await channelClient.inviteMembers(memberIds, message);
 
         verify(() => mockDio.post<String>('/channels/messaging/testid',
-            data: {'invites': members, 'message': message.toJson()})).called(1);
+                data: {'invites': memberIds, 'message': message.toJson()}))
+            .called(1);
       });
 
       test('removeMembers', () async {
@@ -2244,27 +2426,46 @@ void main() {
           tokenProvider: (_) async => '',
         );
         final channelClient = client.channel('messaging', id: 'testid');
-        final members = ['vishal'];
+        final channelModel = ChannelModel(cid: 'messaging:testid');
+
+        when(() => mockDio.post<String>(
+              any(),
+              data: any(named: 'data'),
+            )).thenAnswer((_) async => Response(
+              data: jsonEncode(ChannelState(channel: channelModel)),
+              statusCode: 200,
+              requestOptions: FakeRequestOptions(),
+            ));
+
+        await channelClient.watch();
+
+        final members = [Member(userId: 'vishal')];
+        final memberIds = members.map((e) => e.userId!).toList();
         final message = Message(text: 'test');
 
         when(
           () => mockDio.post<String>(
             '/channels/messaging/testid',
-            data: {'remove_members': members, 'message': message.toJson()},
+            data: {'remove_members': memberIds, 'message': message.toJson()},
           ),
         ).thenAnswer(
           (_) async => Response(
-            data: '{}',
+            data: jsonEncode({
+              'members': members,
+              'message': message,
+              'channel': channelModel,
+            }),
             statusCode: 200,
             requestOptions: FakeRequestOptions(),
           ),
         );
 
-        await channelClient.removeMembers(members, message);
+        await channelClient.removeMembers(memberIds, message);
 
-        verify(() => mockDio.post<String>('/channels/messaging/testid',
-                data: {'remove_members': members, 'message': message.toJson()}))
-            .called(1);
+        verify(() => mockDio.post<String>('/channels/messaging/testid', data: {
+              'remove_members': memberIds,
+              'message': message.toJson()
+            })).called(1);
       });
 
       test('hide', () async {
diff --git a/packages/stream_chat/test/src/api/requests_test.dart b/packages/stream_chat/test/src/api/requests_test.dart
index 1e46fee0..76253403 100644
--- a/packages/stream_chat/test/src/api/requests_test.dart
+++ b/packages/stream_chat/test/src/api/requests_test.dart
@@ -1,5 +1,5 @@
-import 'package:test/test.dart';
 import 'package:stream_chat/stream_chat.dart';
+import 'package:test/test.dart';
 
 void main() {
   group('src/api/requests', () {
@@ -12,7 +12,8 @@ void main() {
     test('PaginationParams', () {
       const option = PaginationParams();
       final j = option.toJson();
-      expect(j, {'limit': 10, 'offset': 0});
+      expect(j, containsPair('limit', 10));
+      expect(j, containsPair('offset', 0));
     });
   });
 }
diff --git a/packages/stream_chat/test/src/api/responses_test.dart b/packages/stream_chat/test/src/api/responses_test.dart
index ad81aeff..f91248af 100644
--- a/packages/stream_chat/test/src/api/responses_test.dart
+++ b/packages/stream_chat/test/src/api/responses_test.dart
@@ -12,7 +12,8 @@ import 'package:stream_chat/stream_chat.dart';
 void main() {
   group('src/api/responses', () {
     test('QueryChannelsResponse', () {
-      const jsonExample = r'''{
+      const jsonExample = r'''
+      {
     "channels": [
         {
             "channel": {
@@ -3432,7 +3433,8 @@ void main() {
     });
 
     test('SendReactionResponse', () {
-      const jsonExample = r'''{"message": {
+      const jsonExample = r'''
+      {"message": {
                     "id": "c6076f11-7768-4a04-bdf2-c43dddd6d666",
                     "text": "What we don't know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.",
                     "html": "\u003cp\u003eWhat we don’t know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.\u003c/p\u003e\n",
@@ -3481,7 +3483,8 @@ void main() {
     });
 
     test('UpdateUsersResponse', () {
-      const jsonExample = '''{"users": {"bbb19d9a-ee50-45bc-84e5-0584e79d0c9e":{
+      const jsonExample = '''
+      {"users": {"bbb19d9a-ee50-45bc-84e5-0584e79d0c9e":{
                         "id": "bbb19d9a-ee50-45bc-84e5-0584e79d0c9e",
                         "role": "user",
                         "created_at": "2020-01-28T22:17:30.826259Z",
@@ -3505,7 +3508,8 @@ void main() {
     });
 
     test('GetMessagesByIdResponse', () {
-      const jsonExample = r'''{"messages":[{
+      const jsonExample = r'''
+      {"messages":[{
                     "id": "c6076f11-7768-4a04-bdf2-c43dddd6d666",
                     "text": "What we don't know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.",
                     "html": "\u003cp\u003eWhat we don’t know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.\u003c/p\u003e\n",
@@ -3536,7 +3540,8 @@ void main() {
     });
 
     test('SendActionResponse', () {
-      const jsonExample = r'''{"message":{
+      const jsonExample = r'''
+      {"message":{
                     "id": "c6076f11-7768-4a04-bdf2-c43dddd6d666",
                     "text": "What we don't know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.",
                     "html": "\u003cp\u003eWhat we don’t know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.\u003c/p\u003e\n",
@@ -3566,7 +3571,8 @@ void main() {
     });
 
     test('UpdateMessageResponse', () {
-      const jsonExample = r'''{"message":{
+      const jsonExample = r'''
+      {"message":{
                     "id": "c6076f11-7768-4a04-bdf2-c43dddd6d666",
                     "text": "What we don't know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.",
                     "html": "\u003cp\u003eWhat we don’t know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.\u003c/p\u003e\n",
@@ -3596,7 +3602,8 @@ void main() {
     });
 
     test('SendMessageResponse', () {
-      const jsonExample = r'''{"message":{
+      const jsonExample = r'''
+      {"message":{
                     "id": "c6076f11-7768-4a04-bdf2-c43dddd6d666",
                     "text": "What we don't know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.",
                     "html": "\u003cp\u003eWhat we don’t know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.\u003c/p\u003e\n",
@@ -3626,7 +3633,8 @@ void main() {
     });
 
     test('GetMessageResponse', () {
-      const jsonExample = r'''{"message":{
+      const jsonExample = r'''
+      {"message":{
                     "id": "c6076f11-7768-4a04-bdf2-c43dddd6d666",
                     "text": "What we don't know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.",
                     "html": "\u003cp\u003eWhat we don’t know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.\u003c/p\u003e\n",
@@ -3656,7 +3664,8 @@ void main() {
     });
 
     test('UpdateChannelResponse', () {
-      const jsonExample = r'''{"message":{
+      const jsonExample = r'''
+      {"message":{
                     "id": "c6076f11-7768-4a04-bdf2-c43dddd6d666",
                     "text": "What we don't know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.",
                     "html": "\u003cp\u003eWhat we don’t know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.\u003c/p\u003e\n",
@@ -3769,7 +3778,8 @@ void main() {
     });
 
     test('InviteMembersResponse', () {
-      const jsonExample = r'''{"message":{
+      const jsonExample = r'''
+      {"message":{
                     "id": "c6076f11-7768-4a04-bdf2-c43dddd6d666",
                     "text": "What we don't know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.",
                     "html": "\u003cp\u003eWhat we don’t know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.\u003c/p\u003e\n",
@@ -3882,7 +3892,8 @@ void main() {
     });
 
     test('RemoveMembersResponse', () {
-      const jsonExample = r'''{"message":{
+      const jsonExample = r'''
+      {"message":{
                     "id": "c6076f11-7768-4a04-bdf2-c43dddd6d666",
                     "text": "What we don't know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.",
                     "html": "\u003cp\u003eWhat we don’t know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.\u003c/p\u003e\n",
@@ -3995,7 +4006,8 @@ void main() {
     });
 
     test('AddMembersResponse', () {
-      const jsonExample = r'''{"message":{
+      const jsonExample = r'''
+      {"message":{
                     "id": "c6076f11-7768-4a04-bdf2-c43dddd6d666",
                     "text": "What we don't know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.",
                     "html": "\u003cp\u003eWhat we don’t know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.\u003c/p\u003e\n",
@@ -4108,7 +4120,8 @@ void main() {
     });
 
     test('AcceptInviteResponse', () {
-      const jsonExample = r'''{"message":{
+      const jsonExample = r'''
+      {"message":{
                     "id": "c6076f11-7768-4a04-bdf2-c43dddd6d666",
                     "text": "What we don't know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.",
                     "html": "\u003cp\u003eWhat we don’t know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.\u003c/p\u003e\n",
@@ -4221,7 +4234,8 @@ void main() {
     });
 
     test('RejectInviteResponse', () {
-      const jsonExample = r'''{"message":{
+      const jsonExample = r'''
+      {"message":{
                     "id": "c6076f11-7768-4a04-bdf2-c43dddd6d666",
                     "text": "What we don't know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.",
                     "html": "\u003cp\u003eWhat we don’t know for sure is whether or not a step-daughter of the bear is assumed to be a farci hourglass.\u003c/p\u003e\n",
diff --git a/packages/stream_chat/test/src/api/websocket_test.dart b/packages/stream_chat/test/src/api/websocket_test.dart
index 5993f0bf..b9c897a6 100644
--- a/packages/stream_chat/test/src/api/websocket_test.dart
+++ b/packages/stream_chat/test/src/api/websocket_test.dart
@@ -12,12 +12,10 @@ import 'package:web_socket_channel/web_socket_channel.dart';
 
 class Functions {
   WebSocketChannel connectFunc(
-    String url, {
-    Iterable<String> protocols,
-    Map<String, dynamic> headers,
-    Duration pingInterval,
+    String? url, {
+    Iterable<String>? protocols,
   }) =>
-      null;
+      WebSocketChannel.connect(Uri());
 
   void handleFunc(Event event) {}
 }
@@ -37,7 +35,7 @@ void main() {
     });
 
     test('should connect with correct parameters', () async {
-      final ConnectWebSocket connectFunc = MockFunctions().connectFunc;
+      final connectFunc = MockFunctions().connectFunc;
       final ws = WebSocket(
         baseUrl: 'baseurl',
         user: User(id: 'testid'),
@@ -75,7 +73,7 @@ void main() {
 
   test('should connect with correct parameters and handle events', () async {
     final handleFunc = MockFunctions().handleFunc;
-    final ConnectWebSocket connectFunc = MockFunctions().connectFunc;
+    final connectFunc = MockFunctions().connectFunc;
     final ws = WebSocket(
       baseUrl: 'baseurl',
       user: User(id: 'testid'),
@@ -111,7 +109,7 @@ void main() {
 
   test('should close correctly the controller', () async {
     final handleFunc = MockFunctions().handleFunc;
-    final ConnectWebSocket connectFunc = MockFunctions().connectFunc;
+    final connectFunc = MockFunctions().connectFunc;
     final ws = WebSocket(
       baseUrl: 'baseurl',
       user: User(id: 'testid'),
@@ -126,8 +124,10 @@ void main() {
     const computedUrl =
         'wss://baseurl/connect?test=true&json=%7B%22payload%22%3A%22test%22%2C%22user_details%22%3A%7B%22id%22%3A%22testid%22%7D%7D';
 
+    final mockWSSink = MockWSSink();
+    when(() => mockWSChannel.sink).thenAnswer((_) => mockWSSink);
+    when(() => mockWSSink.close(any(), any())).thenAnswer((_) async => null);
     when(() => connectFunc(computedUrl)).thenAnswer((_) => mockWSChannel);
-    when(() => mockWSChannel.sink).thenAnswer((_) => MockWSSink());
     when(() => mockWSChannel.stream).thenAnswer((_) => streamController.stream);
 
     final connect = ws.connect().then((_) {
@@ -148,7 +148,7 @@ void main() {
   test('should close correctly the controller while connecting', () async {
     final handleFunc = MockFunctions().handleFunc;
 
-    final ConnectWebSocket connectFunc = MockFunctions().connectFunc;
+    final connectFunc = MockFunctions().connectFunc;
 
     final ws = WebSocket(
       baseUrl: 'baseurl',
@@ -167,8 +167,10 @@ void main() {
     const computedUrl =
         'wss://baseurl/connect?test=true&json=%7B%22payload%22%3A%22test%22%2C%22user_details%22%3A%7B%22id%22%3A%22testid%22%7D%7D';
 
+    final mockWSSink = MockWSSink();
+    when(() => mockWSChannel.sink).thenAnswer((_) => mockWSSink);
+    when(() => mockWSSink.close(any(), any())).thenAnswer((_) async => null);
     when(() => connectFunc(computedUrl)).thenAnswer((_) => mockWSChannel);
-    when(() => mockWSChannel.sink).thenAnswer((_) => MockWSSink());
     when(() => mockWSChannel.stream).thenAnswer((_) => streamController.stream);
 
     ws.connect();
@@ -183,7 +185,7 @@ void main() {
 
   test('should run correctly health check', () async {
     final handleFunc = MockFunctions().handleFunc;
-    final ConnectWebSocket connectFunc = MockFunctions().connectFunc;
+    final connectFunc = MockFunctions().connectFunc;
     final ws = WebSocket(
       baseUrl: 'baseurl',
       user: User(id: 'testid'),
@@ -201,7 +203,8 @@ void main() {
 
     when(() => connectFunc(computedUrl)).thenAnswer((_) => mockWSChannel);
     when(() => mockWSChannel.stream).thenAnswer((_) => streamController.stream);
-    when(() => mockWSChannel.sink).thenReturn(mockWSSink);
+    when(() => mockWSChannel.sink).thenAnswer((_) => mockWSSink);
+    when(() => mockWSSink.close(any(), any())).thenAnswer((_) async => null);
 
     final timer = Timer.periodic(
       const Duration(milliseconds: 1000),
@@ -227,7 +230,7 @@ void main() {
 
   test('should run correctly reconnection check', () async {
     final handleFunc = MockFunctions().handleFunc;
-    final ConnectWebSocket connectFunc = MockFunctions().connectFunc;
+    final connectFunc = MockFunctions().connectFunc;
     Logger.root.level = Level.ALL;
     final ws = WebSocket(
       baseUrl: 'baseurl',
@@ -247,7 +250,8 @@ void main() {
 
     when(() => connectFunc(computedUrl)).thenAnswer((_) => mockWSChannel);
     when(() => mockWSChannel.stream).thenAnswer((_) => streamController.stream);
-    when(() => mockWSChannel.sink).thenReturn(mockWSSink);
+    when(() => mockWSChannel.sink).thenAnswer((_) => mockWSSink);
+    when(() => mockWSSink.close(any(), any())).thenAnswer((_) async => null);
 
     final connect = ws.connect().then((_) {
       streamController.sink.add('{}');
@@ -272,7 +276,7 @@ void main() {
 
   test('should close correctly the controller', () async {
     final handleFunc = MockFunctions().handleFunc;
-    final ConnectWebSocket connectFunc = MockFunctions().connectFunc;
+    final connectFunc = MockFunctions().connectFunc;
     final ws = WebSocket(
       baseUrl: 'baseurl',
       user: User(id: 'testid'),
@@ -290,7 +294,8 @@ void main() {
 
     when(() => connectFunc(computedUrl)).thenAnswer((_) => mockWSChannel);
     when(() => mockWSChannel.stream).thenAnswer((_) => streamController.stream);
-    when(() => mockWSChannel.sink).thenReturn(mockWSSink);
+    when(() => mockWSChannel.sink).thenAnswer((_) => mockWSSink);
+    when(() => mockWSSink.close(any(), any())).thenAnswer((_) async => null);
 
     final connect = ws.connect().then((_) {
       streamController.sink.add('{}');
@@ -309,7 +314,7 @@ void main() {
   });
 
   test('should throw an error', () async {
-    final ConnectWebSocket connectFunc = MockFunctions().connectFunc;
+    final connectFunc = MockFunctions().connectFunc;
     final ws = WebSocket(
       baseUrl: 'baseurl',
       user: User(id: 'testid'),
diff --git a/packages/stream_chat/test/src/client_test.dart b/packages/stream_chat/test/src/client_test.dart
index 6ae8ee3e..c93059d5 100644
--- a/packages/stream_chat/test/src/client_test.dart
+++ b/packages/stream_chat/test/src/client_test.dart
@@ -9,9 +9,9 @@ import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat/src/api/requests.dart';
 import 'package:stream_chat/src/client.dart';
 import 'package:stream_chat/src/exceptions.dart';
+import 'package:stream_chat/src/models/channel_model.dart';
 import 'package:stream_chat/src/models/message.dart';
 import 'package:stream_chat/src/models/user.dart';
-import 'package:stream_chat/src/models/channel_model.dart';
 import 'package:test/test.dart';
 
 class MockDio extends Mock implements DioForNative {}
@@ -21,7 +21,7 @@ class FakeRequestOptions extends Fake implements RequestOptions {}
 class MockHttpClientAdapter extends Mock implements HttpClientAdapter {}
 
 class Functions {
-  Future<String> tokenProvider(String userId) => null;
+  Future<String> tokenProvider(String userId) async => '';
 }
 
 class MockFunctions extends Mock implements Functions {}
@@ -155,7 +155,9 @@ void main() {
             'sort': sortOptions,
           }
             ..addAll(options)
-            ..addAll(paginationParams.toJson())),
+            ..addAll(paginationParams
+                .toJson()
+                .map((key, value) => MapEntry(key, value as Object)))),
         };
 
         when(
@@ -735,7 +737,9 @@ void main() {
         when(() => mockDio.interceptors).thenReturn(Interceptors());
 
         final client = StreamChatClient('api-key', httpClient: mockDio);
-        final message = Message(id: 'test', updatedAt: DateTime.now());
+        final message = Message(
+          id: 'test',
+        );
 
         when(
           () => mockDio.post<String>(
@@ -744,7 +748,7 @@ void main() {
           ),
         ).thenAnswer(
           (_) async => Response(
-            data: '{}',
+            data: jsonEncode({'message': message}),
             statusCode: 200,
             requestOptions: FakeRequestOptions(),
           ),
@@ -789,7 +793,7 @@ void main() {
 
         when(() => mockDio.get<String>('/messages/$messageId')).thenAnswer(
           (_) async => Response(
-            data: '{}',
+            data: jsonEncode({'message': Message(id: messageId)}),
             statusCode: 200,
             requestOptions: FakeRequestOptions(),
           ),
@@ -1111,7 +1115,7 @@ void main() {
             ),
           ).thenAnswer(
             (_) async => Response(
-              data: '{}',
+              data: jsonEncode({'message': message}),
               statusCode: 200,
               requestOptions: FakeRequestOptions(),
             ),
@@ -1133,7 +1137,7 @@ void main() {
             ),
           ).thenAnswer(
             (_) async => Response(
-              data: '{}',
+              data: jsonEncode({'message': message}),
               statusCode: 200,
               requestOptions: FakeRequestOptions(),
             ),
@@ -1173,7 +1177,7 @@ void main() {
           ),
         ).thenAnswer(
           (_) async => Response(
-            data: '{}',
+            data: jsonEncode({'channel': ChannelModel(cid: 'messaging:test')}),
             statusCode: 200,
             requestOptions: FakeRequestOptions(),
           ),
diff --git a/packages/stream_chat/test/src/models/action_test.dart b/packages/stream_chat/test/src/models/action_test.dart
index 5d142953..22e66078 100644
--- a/packages/stream_chat/test/src/models/action_test.dart
+++ b/packages/stream_chat/test/src/models/action_test.dart
@@ -5,7 +5,8 @@ import 'package:stream_chat/src/models/action.dart';
 
 void main() {
   group('src/models/action', () {
-    const jsonExample = '''{
+    const jsonExample = '''
+    {
     "name": "name",
     "style": "style",
     "text": "text",
diff --git a/packages/stream_chat/test/src/models/attachment_test.dart b/packages/stream_chat/test/src/models/attachment_test.dart
index 3124ddd2..1342e72e 100644
--- a/packages/stream_chat/test/src/models/attachment_test.dart
+++ b/packages/stream_chat/test/src/models/attachment_test.dart
@@ -1,12 +1,13 @@
 import 'dart:convert';
-import 'package:stream_chat/src/models/attachment.dart';
-import 'package:stream_chat/src/models/action.dart';
 
+import 'package:stream_chat/src/models/action.dart';
+import 'package:stream_chat/src/models/attachment.dart';
 import 'package:test/test.dart';
 
 void main() {
   group('src/models/attachment', () {
-    const jsonExample = '''{
+    const jsonExample = '''
+    {
   "type": "giphy",
   "title": "awesome",
   "title_link": "https://giphy.com/gifs/nrkp3-dance-happy-3o7TKnCdBx5cMg0qti",
@@ -66,7 +67,8 @@ void main() {
           'type': 'image',
           'title': 'soo',
           'title_link':
-              'https://giphy.com/gifs/nrkp3-dance-happy-3o7TKnCdBx5cMg0qti'
+              'https://giphy.com/gifs/nrkp3-dance-happy-3o7TKnCdBx5cMg0qti',
+          'actions': [],
         },
       );
     });
diff --git a/packages/stream_chat/test/src/models/channel_state_test.dart b/packages/stream_chat/test/src/models/channel_state_test.dart
index c2d69b2b..afe384f5 100644
--- a/packages/stream_chat/test/src/models/channel_state_test.dart
+++ b/packages/stream_chat/test/src/models/channel_state_test.dart
@@ -1,16 +1,17 @@
 import 'dart:convert';
 
-import 'package:test/test.dart';
 import 'package:stream_chat/src/models/channel_config.dart';
 import 'package:stream_chat/src/models/channel_state.dart';
 import 'package:stream_chat/src/models/command.dart';
 import 'package:stream_chat/src/models/message.dart';
 import 'package:stream_chat/src/models/user.dart';
 import 'package:stream_chat/stream_chat.dart';
+import 'package:test/test.dart';
 
 void main() {
   group('src/models/channel_state', () {
-    const jsonExample = '''{
+    const jsonExample = '''
+  {
    "channel": {
      "id": "dev",
      "type": "team",
@@ -844,26 +845,26 @@ void main() {
 
     test('should parse json correctly', () {
       final channelState = ChannelState.fromJson(json.decode(jsonExample));
-      expect(channelState.channel.cid, 'team:dev');
-      expect(channelState.channel.id, 'dev');
-      expect(channelState.channel.team, 'test');
-      expect(channelState.channel.type, 'team');
-      expect(channelState.channel.config, isA<ChannelConfig>());
-      expect(channelState.channel.config, isNotNull);
-      expect(channelState.channel.config.commands, hasLength(1));
-      expect(channelState.channel.config.commands[0], isA<Command>());
-      expect(channelState.channel.lastMessageAt,
+      expect(channelState.channel?.cid, 'team:dev');
+      expect(channelState.channel?.id, 'dev');
+      expect(channelState.channel?.team, 'test');
+      expect(channelState.channel?.type, 'team');
+      expect(channelState.channel?.config, isA<ChannelConfig>());
+      expect(channelState.channel?.config, isNotNull);
+      expect(channelState.channel?.config.commands, hasLength(1));
+      expect(channelState.channel?.config.commands[0], isA<Command>());
+      expect(channelState.channel?.lastMessageAt,
           DateTime.parse('2020-01-30T13:43:41.062362Z'));
-      expect(channelState.channel.createdAt,
+      expect(channelState.channel?.createdAt,
           DateTime.parse('2019-04-03T18:43:33.213373Z'));
-      expect(channelState.channel.updatedAt,
+      expect(channelState.channel?.updatedAt,
           DateTime.parse('2019-04-03T18:43:33.213374Z'));
-      expect(channelState.channel.createdBy, isA<User>());
-      expect(channelState.channel.frozen, true);
-      expect(channelState.channel.extraData['example'], 1);
-      expect(channelState.channel.extraData['name'], '#dev');
+      expect(channelState.channel?.createdBy, isA<User>());
+      expect(channelState.channel?.frozen, true);
+      expect(channelState.channel?.extraData!['example'], 1);
+      expect(channelState.channel?.extraData!['name'], '#dev');
       expect(
-        channelState.channel.extraData['image'],
+        channelState.channel?.extraData!['image'],
         'https://cdn.chrisshort.net/testing-certificate-chains-in-go/GOPHER_MIC_DROP.png',
       );
       expect(channelState.messages, hasLength(25));
@@ -888,8 +889,8 @@ void main() {
               "image": "https://cdn.chrisshort.net/testing-certificate-chains-in-go/GOPHER_MIC_DROP.png",
               "example": 1
             },
-            "watchers": null,
-            "read": null,
+            "watchers": [],
+            "read": [],
             "messages": [
               {
                 "id": "dry-meadow-0-2b73cc8b-cd86-4a01-8d40-bd82ad07a030",
@@ -901,7 +902,7 @@ void main() {
                 "show_in_channel": null,
                 "mentioned_users": [],
                 "status": "SENT",
-            "skip_push": null,
+                "skip_push": false,
                 "silent": false,
                 "pinned": false,
                 "pinned_at": null,
@@ -918,7 +919,7 @@ void main() {
                 "show_in_channel": null,
                 "mentioned_users": [],
                 "status": "SENT",
-            "skip_push": null,
+                "skip_push": false,
                 "silent": false,
                 "pinned": false,
                 "pinned_at": null,
@@ -928,7 +929,7 @@ void main() {
               {
                 "id": "dry-meadow-0-53e6299f-9b97-4a9c-a27e-7e2dde49b7e0",
                 "text": "test message",
-            "skip_push": null,
+                "skip_push": false,
                 "attachments": [],
                 "parent_id": null,
                 "quoted_message": null,
@@ -951,7 +952,7 @@ void main() {
                 "quoted_message_id": null,
                 "show_in_channel": null,
                 "mentioned_users": [],
-            "skip_push": null,
+                "skip_push": false,
                 "status": "SENT",
                 "silent": false,
                 "pinned": false,
@@ -963,7 +964,7 @@ void main() {
                 "id": "dry-meadow-0-64d7970f-ede8-4b31-9738-1bc1756d2bfe",
                 "text": "test",
                 "attachments": [],
-            "skip_push": null,
+                "skip_push": false,
                 "parent_id": null,
                 "quoted_message": null,
                 "quoted_message_id": null,
@@ -981,7 +982,7 @@ void main() {
                 "text": "hi",
                 "attachments": [],
                 "parent_id": null,
-            "skip_push": null,
+                "skip_push": false,
                 "quoted_message": null,
                 "quoted_message_id": null,
                 "show_in_channel": null,
@@ -999,7 +1000,7 @@ void main() {
                 "attachments": [],
                 "parent_id": null,
                 "quoted_message": null,
-            "skip_push": null,
+                "skip_push": false,
                 "quoted_message_id": null,
                 "show_in_channel": null,
                 "mentioned_users": [],
@@ -1022,7 +1023,7 @@ void main() {
                 "status": "SENT",
                 "silent": false,
                 "pinned": false,
-            "skip_push": null,
+                "skip_push": false,
                 "pinned_at": null,
                 "pin_expires": null,
                 "pinned_by": null
@@ -1040,7 +1041,7 @@ void main() {
                 "silent": false,
                 "pinned": false,
                 "pinned_at": null,
-            "skip_push": null,
+                "skip_push": false,
                 "pin_expires": null,
                 "pinned_by": null
               },
@@ -1052,7 +1053,7 @@ void main() {
                 "quoted_message": null,
                 "quoted_message_id": null,
                 "show_in_channel": null,
-            "skip_push": null,
+                "skip_push": false,
                 "mentioned_users": [],
                 "status": "SENT",
                 "silent": false,
@@ -1070,7 +1071,7 @@ void main() {
                 "quoted_message_id": null,
                 "show_in_channel": null,
                 "mentioned_users": [],
-            "skip_push": null,
+                "skip_push": false,
                 "status": "SENT",
                 "silent": false,
                 "pinned": false,
@@ -1089,7 +1090,7 @@ void main() {
                 "mentioned_users": [],
                 "status": "SENT",
                 "silent": false,
-            "skip_push": null,
+                "skip_push": false,
                 "pinned": false,
                 "pinned_at": null,
                 "pin_expires": null,
@@ -1099,7 +1100,7 @@ void main() {
                 "id": "icy-recipe-7-935c396e-ddf8-4a9a-951c-0a12fa5bf055",
                 "text": "what are you doing?",
                 "attachments": [],
-            "skip_push": null,
+                "skip_push": false,
                 "parent_id": null,
                 "quoted_message": null,
                 "quoted_message_id": null,
@@ -1117,7 +1118,7 @@ void main() {
                 "text": "👍",
                 "attachments": [],
                 "parent_id": null,
-            "skip_push": null,
+                "skip_push": false,
                 "quoted_message": null,
                 "quoted_message_id": null,
                 "show_in_channel": null,
@@ -1133,7 +1134,7 @@ void main() {
                 "id": "snowy-credit-3-3e0c1a0d-d22f-42ee-b2a1-f9f49477bf21",
                 "text": "sdasas",
                 "attachments": [],
-            "skip_push": null,
+                "skip_push": false,
                 "parent_id": null,
                 "quoted_message": null,
                 "quoted_message_id": null,
@@ -1154,7 +1155,7 @@ void main() {
                 "quoted_message": null,
                 "quoted_message_id": null,
                 "show_in_channel": null,
-            "skip_push": null,
+                "skip_push": false,
                 "mentioned_users": [],
                 "status": "SENT",
                 "silent": false,
@@ -1167,7 +1168,7 @@ void main() {
                 "id": "snowy-credit-3-cfaf0b46-1daa-49c5-947c-b16d6697487d",
                 "text": "nhisagdhsadz",
                 "attachments": [],
-            "skip_push": null,
+                "skip_push": false,
                 "parent_id": null,
                 "quoted_message": null,
                 "quoted_message_id": null,
@@ -1186,7 +1187,7 @@ void main() {
                 "attachments": [],
                 "parent_id": null,
                 "quoted_message": null,
-            "skip_push": null,
+                "skip_push": false,
                 "quoted_message_id": null,
                 "show_in_channel": null,
                 "mentioned_users": [],
@@ -1203,7 +1204,7 @@ void main() {
                 "attachments": [],
                 "parent_id": null,
                 "quoted_message": null,
-            "skip_push": null,
+                "skip_push": false,
                 "quoted_message_id": null,
                 "show_in_channel": null,
                 "mentioned_users": [],
@@ -1211,7 +1212,7 @@ void main() {
                 "silent": false,
                 "pinned": false,
                 "pinned_at": null,
-            "skip_push": null,
+                "skip_push": false,
                 "pin_expires": null,
                 "pinned_by": null
               },
@@ -1228,7 +1229,7 @@ void main() {
                 "silent": false,
                 "pinned": false,
                 "pinned_at": null,
-            "skip_push": null,
+                "skip_push": false,
                 "pin_expires": null,
                 "pinned_by": null
               },
@@ -1245,7 +1246,7 @@ void main() {
                 "silent": false,
                 "pinned": false,
                 "pinned_at": null,
-            "skip_push": null,
+                "skip_push": false,
                 "pin_expires": null,
                 "pinned_by": null
               },
@@ -1262,7 +1263,7 @@ void main() {
                 "silent": false,
                 "pinned": false,
                 "pinned_at": null,
-            "skip_push": null,
+                "skip_push": false,
                 "pin_expires": null,
                 "pinned_by": null
               },
@@ -1279,7 +1280,7 @@ void main() {
                 "silent": false,
                 "pinned": false,
                 "pinned_at": null,
-            "skip_push": null,
+                "skip_push": false,
                 "pin_expires": null,
                 "pinned_by": null
               },
@@ -1296,7 +1297,7 @@ void main() {
                 "silent": false,
                 "pinned": false,
                 "pinned_at": null,
-            "skip_push": null,
+                "skip_push": false,
                 "pin_expires": null,
                 "pinned_by": null
               },
@@ -1313,7 +1314,7 @@ void main() {
                 "silent": false,
                 "pinned": false,
                 "pinned_at": null,
-            "skip_push": null,
+                "skip_push": false,
                 "pin_expires": null,
                 "pinned_by": null
               }
@@ -1329,10 +1330,10 @@ void main() {
         members: [],
         messages:
             (j['messages'] as List).map((m) => Message.fromJson(m)).toList(),
-        read: null,
+        read: [],
         watcherCount: 5,
         pinnedMessages: [],
-        watchers: null,
+        watchers: [],
       );
 
       expect(
diff --git a/packages/stream_chat/test/src/models/channel_test.dart b/packages/stream_chat/test/src/models/channel_test.dart
index 9f6aa5b7..01c06fee 100644
--- a/packages/stream_chat/test/src/models/channel_test.dart
+++ b/packages/stream_chat/test/src/models/channel_test.dart
@@ -1,7 +1,7 @@
 import 'dart:convert';
 
-import 'package:test/test.dart';
 import 'package:stream_chat/src/models/channel_model.dart';
+import 'package:test/test.dart';
 
 void main() {
   group('src/models/channel', () {
@@ -9,7 +9,7 @@ void main() {
       {
         "id": "test",
         "type": "livestream",
-        "cid": "test:livestream",
+        "cid": "livestream:test",
         "cats": true,
         "fruit": ["bananas", "apples"]
       }      
@@ -19,9 +19,9 @@ void main() {
       final channel = ChannelModel.fromJson(json.decode(jsonExample));
       expect(channel.id, equals('test'));
       expect(channel.type, equals('livestream'));
-      expect(channel.cid, equals('test:livestream'));
-      expect(channel.extraData['cats'], equals(true));
-      expect(channel.extraData['fruit'], equals(['bananas', 'apples']));
+      expect(channel.cid, equals('livestream:test'));
+      expect(channel.extraData!['cats'], equals(true));
+      expect(channel.extraData!['fruit'], equals(['bananas', 'apples']));
     });
 
     test('should serialize to json correctly', () {
@@ -34,7 +34,7 @@ void main() {
 
       expect(
         channel.toJson(),
-        {'id': 'id', 'type': 'type', 'name': 'cool'},
+        {'id': 'id', 'type': 'type', 'frozen': false, 'name': 'cool'},
       );
     });
 
@@ -44,7 +44,6 @@ void main() {
         id: 'id',
         cid: 'a:a',
         extraData: {'name': 'cool'},
-        frozen: false,
       );
 
       expect(
diff --git a/packages/stream_chat/test/src/models/device_test.dart b/packages/stream_chat/test/src/models/device_test.dart
index 27a94982..5cbf015d 100644
--- a/packages/stream_chat/test/src/models/device_test.dart
+++ b/packages/stream_chat/test/src/models/device_test.dart
@@ -5,7 +5,8 @@ import 'package:stream_chat/src/models/device.dart';
 
 void main() {
   group('src/models/device', () {
-    const jsonExample = '''{
+    const jsonExample = '''
+    {
       "id": "device-id",
       "push_provider": "push-provider"
     }''';
diff --git a/packages/stream_chat/test/src/models/event_test.dart b/packages/stream_chat/test/src/models/event_test.dart
index a7c669df..96efa844 100644
--- a/packages/stream_chat/test/src/models/event_test.dart
+++ b/packages/stream_chat/test/src/models/event_test.dart
@@ -1,9 +1,9 @@
 import 'dart:convert';
 
-import 'package:test/test.dart';
 import 'package:stream_chat/src/models/event.dart';
 import 'package:stream_chat/src/models/own_user.dart';
 import 'package:stream_chat/stream_chat.dart';
+import 'package:test/test.dart';
 
 void main() {
   group('src/models/event', () {
@@ -47,6 +47,7 @@ void main() {
       expect(event.createdAt, isA<DateTime>());
       expect(event.me, isA<OwnUser>());
       expect(event.user, isA<User>());
+      expect(event.isLocal, false);
     });
 
     test('should serialize to json correctly', () {
@@ -77,11 +78,11 @@ void main() {
           'total_unread_count': 1,
           'unread_channels': 1,
           'online': true,
-          'is_local': true,
           'member': null,
           'channel_id': null,
           'channel_type': null,
           'parent_id': null,
+          'is_local': true,
         },
       );
     });
diff --git a/packages/stream_chat/test/src/models/message_test.dart b/packages/stream_chat/test/src/models/message_test.dart
index 0898e902..1219e137 100644
--- a/packages/stream_chat/test/src/models/message_test.dart
+++ b/packages/stream_chat/test/src/models/message_test.dart
@@ -1,14 +1,15 @@
 import 'dart:convert';
 
-import 'package:test/test.dart';
 import 'package:stream_chat/src/models/attachment.dart';
 import 'package:stream_chat/src/models/message.dart';
 import 'package:stream_chat/src/models/reaction.dart';
 import 'package:stream_chat/src/models/user.dart';
+import 'package:test/test.dart';
 
 void main() {
   group('src/models/message', () {
-    const jsonExample = r'''{
+    const jsonExample = r'''
+    {
       "id": "4637f7e4-a06b-42db-ba5a-8d8270dd926f",
       "text": "https://giphy.com/gifs/the-lion-king-live-action-5zvN79uTGfLMOVfQaA",
       "type": "regular",
@@ -101,9 +102,8 @@ void main() {
         id: '4637f7e4-a06b-42db-ba5a-8d8270dd926f',
         text:
             'https://giphy.com/gifs/the-lion-king-live-action-5zvN79uTGfLMOVfQaA',
-        silent: false,
         attachments: [
-          Attachment.fromJson({
+          Attachment.fromJson(const {
             'type': 'video',
             'author_name': 'GIPHY',
             'title': 'The Lion King Disney GIF - Find \u0026 Share on GIPHY',
@@ -123,7 +123,7 @@ void main() {
         ],
         showInChannel: true,
         parentId: 'parentId',
-        extraData: {'hey': 'test'},
+        extraData: const {'hey': 'test'},
       );
 
       expect(
@@ -133,7 +133,7 @@ void main() {
             "id": "4637f7e4-a06b-42db-ba5a-8d8270dd926f",
             "text": "https://giphy.com/gifs/the-lion-king-live-action-5zvN79uTGfLMOVfQaA",
             "silent": false,
-            "skip_push": null,
+            "skip_push": false,
             "attachments": [
               {
                 "type": "video",
@@ -144,10 +144,11 @@ void main() {
                 "og_scrape_url": "https://giphy.com/gifs/the-lion-king-live-action-5zvN79uTGfLMOVfQaA",
                 "image_url": "https://media.giphy.com/media/5zvN79uTGfLMOVfQaA/giphy.gif",
                 "author_name": "GIPHY",
-                "asset_url": "https://media.giphy.com/media/5zvN79uTGfLMOVfQaA/giphy.mp4"
+                "asset_url": "https://media.giphy.com/media/5zvN79uTGfLMOVfQaA/giphy.mp4",
+                "actions": []
               }
             ],
-            "mentioned_users": null,
+            "mentioned_users": [],
             "parent_id": "parentId",
             "quoted_message": null,
             "quoted_message_id": null,
diff --git a/packages/stream_chat/test/src/models/reaction_test.dart b/packages/stream_chat/test/src/models/reaction_test.dart
index 2a1d5431..795e2967 100644
--- a/packages/stream_chat/test/src/models/reaction_test.dart
+++ b/packages/stream_chat/test/src/models/reaction_test.dart
@@ -1,8 +1,8 @@
 import 'dart:convert';
 
-import 'package:test/test.dart';
 import 'package:stream_chat/src/models/reaction.dart';
 import 'package:stream_chat/src/models/user.dart';
+import 'package:test/test.dart';
 
 void main() {
   group('src/models/reaction', () {
@@ -33,8 +33,8 @@ void main() {
       expect(reaction.createdAt, DateTime.parse('2020-01-28T22:17:31.108742Z'));
       expect(reaction.type, 'wow');
       expect(
-        reaction.user.toJson(),
-        User.init('2de0297c-f3f2-489d-b930-ef77342edccf', extraData: {
+        reaction.user?.toJson(),
+        User(id: '2de0297c-f3f2-489d-b930-ef77342edccf', extraData: {
           'image': 'https://randomuser.me/api/portraits/women/45.jpg',
           'name': 'Daisy Morgan'
         }).toJson(),
@@ -49,7 +49,7 @@ void main() {
         messageId: '76cd8c82-b557-4e48-9d12-87995d3a0e04',
         createdAt: DateTime.parse('2020-01-28T22:17:31.108742Z'),
         type: 'wow',
-        user: User.init('2de0297c-f3f2-489d-b930-ef77342edccf', extraData: {
+        user: User(id: '2de0297c-f3f2-489d-b930-ef77342edccf', extraData: {
           'image': 'https://randomuser.me/api/portraits/women/45.jpg',
           'name': 'Daisy Morgan'
         }),
diff --git a/packages/stream_chat/test/src/models/read_test.dart b/packages/stream_chat/test/src/models/read_test.dart
index 9fd68b6a..66efe809 100644
--- a/packages/stream_chat/test/src/models/read_test.dart
+++ b/packages/stream_chat/test/src/models/read_test.dart
@@ -26,7 +26,7 @@ void main() {
     test('should serialize to json correctly', () {
       final read = Read(
         lastRead: DateTime.parse('2020-01-28T22:17:30.966485504Z'),
-        user: User.init('bbb19d9a-ee50-45bc-84e5-0584e79d0c9e'),
+        user: User(id: 'bbb19d9a-ee50-45bc-84e5-0584e79d0c9e'),
         unreadMessages: 10,
       );
 
diff --git a/packages/stream_chat/test/src/models/serialization_test.dart b/packages/stream_chat/test/src/models/serialization_test.dart
index e8a2de3f..9e64caad 100644
--- a/packages/stream_chat/test/src/models/serialization_test.dart
+++ b/packages/stream_chat/test/src/models/serialization_test.dart
@@ -49,12 +49,12 @@ void main() {
     });
 
     test('should return null', () {
-      final result = Serialization.moveToExtraDataFromRoot(null, [
+      final result = Serialization.moveToExtraDataFromRoot({}, [
         'prop1',
         'prop2',
       ]);
 
-      expect(result, null);
+      expect(result, {'extra_data': {}});
     });
   });
 }
diff --git a/packages/stream_chat/test/src/models/user_test.dart b/packages/stream_chat/test/src/models/user_test.dart
index 0a307126..8f56f7e1 100644
--- a/packages/stream_chat/test/src/models/user_test.dart
+++ b/packages/stream_chat/test/src/models/user_test.dart
@@ -1,13 +1,14 @@
 import 'dart:convert';
 
-import 'package:test/test.dart';
 import 'package:stream_chat/src/models/user.dart';
+import 'package:test/test.dart';
 
 void main() {
   group('src/models/user', () {
     const jsonExample = '''
       {
-        "id": "bbb19d9a-ee50-45bc-84e5-0584e79d0c9e"
+        "id": "bbb19d9a-ee50-45bc-84e5-0584e79d0c9e",
+        "role": "test-role"
       }     
       ''';
 
diff --git a/packages/stream_chat/test/version_test.dart b/packages/stream_chat/test/version_test.dart
index 55b1818a..9bbd446f 100644
--- a/packages/stream_chat/test/version_test.dart
+++ b/packages/stream_chat/test/version_test.dart
@@ -17,8 +17,8 @@ void main() {
     final String pubspecPath = '${Directory.current.path}/pubspec.yaml';
     final String pubspec = File(pubspecPath).readAsStringSync();
     final RegExp regex = RegExp('version:\s*(.*)');
-    final RegExpMatch match = regex.firstMatch(pubspec);
+    final RegExpMatch? match = regex.firstMatch(pubspec);
     expect(match, isNotNull);
-    expect(PACKAGE_VERSION, match.group(1).trim());
+    expect(PACKAGE_VERSION, match?.group(1)?.trim());
   });
 }
diff --git a/packages/stream_chat_flutter/pubspec.yaml b/packages/stream_chat_flutter/pubspec.yaml
index 522a7203..ffee617b 100644
--- a/packages/stream_chat_flutter/pubspec.yaml
+++ b/packages/stream_chat_flutter/pubspec.yaml
@@ -43,7 +43,7 @@ dependencies:
   ezanimation: ^0.4.1
   synchronized: ^3.0.0
   characters: ^1.0.0
-  dio: ">=4.0.0-prev3 <4.0.0"
+  dio: ^4.0.0
   path_provider: ^2.0.0
   video_thumbnail: ^0.2.5+1
 
diff --git a/packages/stream_chat_flutter/test/src/message_reactions_modal_test.dart b/packages/stream_chat_flutter/test/src/message_reactions_modal_test.dart
index 044eb693..8745cb45 100644
--- a/packages/stream_chat_flutter/test/src/message_reactions_modal_test.dart
+++ b/packages/stream_chat_flutter/test/src/message_reactions_modal_test.dart
@@ -90,6 +90,7 @@ void main() {
           Reaction(
             messageId: 'test',
             user: User(id: 'testid'),
+            type: 'test',
           ),
         ],
       );