diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3c8a2ff..3f0417f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,7 +1,9 @@
-## v4.2.12 (Apr 24, 2024)
+## v4.2.13 (Apr 30, 2024)
+
+### Improvements
+- Fixed the bugs regarding session update
 
-### Breaking changes
-- The return type for `getUndeliveredMembers()` was updated from `List<Member>` to `List<Member>?`
+## v4.2.12 (Apr 24, 2024)
 
 ### Features
 - Updated dependency range for `connectivity_plus` package from `^5.0.1` to `>=5.0.1 <7.0.0`
@@ -10,6 +12,9 @@
 - Fixed `MessageCollection` regarding `resetMyHistory()` in `GroupChannel`
 - Fixed `removeFailedMessage()` and `removeAllFailedMessages()` in `MessageCollection`
 - Fixed the bugs regarding message change log, pending message removal, typing status and delivered status
+- Added improvements on `getUndeliveredMembers()` method to prevent a potential problem
+  The return type for `getUndeliveredMembers()` was updated from `List<Member>` to `List<Member>?`
+  Please update this part of your code if you use `getUndeliveredMembers()`
 - Improved stability
 
 ## v4.2.11 (Apr 18, 2024)
diff --git a/README.md b/README.md
index 9aac8fc..8268a79 100644
--- a/README.md
+++ b/README.md
@@ -50,7 +50,7 @@ Before installing Sendbird Chat SDK, you need to create a Sendbird application o
 
 ```yaml
 dependencies:
-  sendbird_chat_sdk: ^4.2.12
+  sendbird_chat_sdk: ^4.2.13
 ```
 
 - Run `flutter pub get` command in your project directory.
diff --git a/lib/src/internal/main/chat/chat.dart b/lib/src/internal/main/chat/chat.dart
index 14fd16a..5b22c6b 100644
--- a/lib/src/internal/main/chat/chat.dart
+++ b/lib/src/internal/main/chat/chat.dart
@@ -62,7 +62,7 @@ part 'chat_notifications.dart';
 part 'chat_push.dart';
 part 'chat_user.dart';
 
-const sdkVersion = '4.2.12';
+const sdkVersion = '4.2.13';
 
 // Internal implementation for main class. Do not directly access this class.
 class Chat with WidgetsBindingObserver {
diff --git a/lib/src/internal/main/chat_manager/command_manager.dart b/lib/src/internal/main/chat_manager/command_manager.dart
index 0c9dded..dfefd42 100644
--- a/lib/src/internal/main/chat_manager/command_manager.dart
+++ b/lib/src/internal/main/chat_manager/command_manager.dart
@@ -377,8 +377,8 @@ class CommandManager {
     } else if (cmd.payload['expires_in'] != null
         ? cmd.payload['expires_in'] < 0
         : false) {
-      // If session token is expired, then log out
       await _chat.connectionManager.disconnect(logout: true);
+      _chat.eventManager.notifySessionClosed();
     } else {
       await _chat.sessionManager.updateSessionKey();
     }
@@ -707,7 +707,6 @@ class CommandManager {
         'cmd: ${cmd.cmd}, errorMessage: ${cmd.errorMessage ?? ''}');
 
     if (cmd.errorCode == SendbirdError.sessionKeyExpired) {
-      await _chat.connectionManager.disconnect(logout: true);
       await _chat.sessionManager.updateSessionKey();
     } else if (cmd.errorCode == SendbirdError.accessTokenRevoked) {
       if (_chat.chatContext.loginCompleter != null &&
diff --git a/lib/src/internal/main/chat_manager/session_manager.dart b/lib/src/internal/main/chat_manager/session_manager.dart
index 4a9ea36..f5ec32e 100644
--- a/lib/src/internal/main/chat_manager/session_manager.dart
+++ b/lib/src/internal/main/chat_manager/session_manager.dart
@@ -84,11 +84,11 @@ class SessionManager {
 
     setSessionKey(null);
 
-    // If websocket exists, ws request to update session key
-    if (_chat.connectionManager.isConnected()) {
-      await _chat.commandManager.updateSessionKey();
-      return;
-    }
+    // If websocket exists, ws request to update session key => Check server error
+    // if (_chat.connectionManager.isConnected()) {
+    //   await _chat.commandManager.updateSessionKey();
+    //   return;
+    // }
 
     final completer = Completer();
     _updateSessionKeyCompleterList.add(completer);
diff --git a/pubspec.yaml b/pubspec.yaml
index c656d87..0f64e9a 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: sendbird_chat_sdk
 description: With Sendbird Chat for Flutter, you can easily build an in-app chat with all the essential messaging features.
-version: 4.2.12
+version: 4.2.13
 homepage: https://sendbird.com
 repository: https://github.com/sendbird/sendbird-chat-sdk-flutter
 documentation: https://sendbird.com/docs/chat/sdk/v4/flutter/getting-started/send-first-message