diff --git a/lib/content_views/approach_area_page.dart b/lib/content_views/approach_area_page.dart
index 5d79ffe..14c02ba 100644
--- a/lib/content_views/approach_area_page.dart
+++ b/lib/content_views/approach_area_page.dart
@@ -1,7 +1,7 @@
 
 import 'package:flutter/material.dart';
 import 'package:isar/isar.dart';
-import 'package:mqtt_client/mqtt_client.dart';
+import 'package:mqtt5_client/mqtt5_client.dart';
 import 'package:stadtbote/content_views/utils/content_view_widget.dart';
 import 'package:stadtbote/content_views/utils/header_info.dart';
 import 'package:stadtbote/main.dart';
diff --git a/lib/content_views/assigned_jobs_page.dart b/lib/content_views/assigned_jobs_page.dart
index b35cee5..a445077 100644
--- a/lib/content_views/assigned_jobs_page.dart
+++ b/lib/content_views/assigned_jobs_page.dart
@@ -2,7 +2,7 @@
 import 'package:expandable/expandable.dart';
 import 'package:flutter/material.dart';
 import 'package:isar/isar.dart';
-import 'package:mqtt_client/mqtt_client.dart';
+import 'package:mqtt5_client/mqtt5_client.dart';
 import 'package:stadtbote/content_views/utils/content_view_widget.dart';
 import 'package:stadtbote/content_views/utils/header_info.dart';
 import 'package:intl/intl.dart';
diff --git a/lib/content_views/main_page.dart b/lib/content_views/main_page.dart
index b2fdc0a..5ab0980 100644
--- a/lib/content_views/main_page.dart
+++ b/lib/content_views/main_page.dart
@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:isar/isar.dart';
-import 'package:mqtt_client/mqtt_client.dart';
+import 'package:mqtt5_client/mqtt5_client.dart';
 import 'package:stadtbote/content_views/accepted_jobs_page.dart';
 import 'package:stadtbote/content_views/approach_area_page.dart';
 import 'package:stadtbote/content_views/assigned_jobs_page.dart';
diff --git a/lib/content_views/messages_page.dart b/lib/content_views/messages_page.dart
index 6ae0a12..bb06101 100644
--- a/lib/content_views/messages_page.dart
+++ b/lib/content_views/messages_page.dart
@@ -3,7 +3,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter_chat_ui/flutter_chat_ui.dart';
 import 'package:flutter_chat_types/flutter_chat_types.dart' as types;
 import 'package:isar/isar.dart';
-import 'package:mqtt_client/mqtt_client.dart';
+import 'package:mqtt5_client/mqtt5_client.dart';
 import 'package:stadtbote/content_views/utils/content_view_widget.dart';
 import 'package:stadtbote/content_views/utils/header_info.dart';
 import 'package:stadtbote/main.dart';
diff --git a/lib/content_views/task_list_page.dart b/lib/content_views/task_list_page.dart
index 29b7bcb..6c960f4 100644
--- a/lib/content_views/task_list_page.dart
+++ b/lib/content_views/task_list_page.dart
@@ -4,7 +4,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:intl/intl.dart';
 import 'package:isar/isar.dart';
-import 'package:mqtt_client/mqtt_client.dart';
+import 'package:mqtt5_client/mqtt5_client.dart';
 import 'package:stadtbote/content_views/utils/content_view_widget.dart';
 import 'package:stadtbote/content_views/utils/header_info.dart';
 import 'package:stadtbote/messages/pop_content_view_message.dart';
diff --git a/lib/popups/accept_jobs_popup.dart b/lib/popups/accept_jobs_popup.dart
index d9fc841..3c3361e 100644
--- a/lib/popups/accept_jobs_popup.dart
+++ b/lib/popups/accept_jobs_popup.dart
@@ -4,7 +4,7 @@ import 'dart:math';
 import 'package:expandable/expandable.dart';
 import 'package:flutter/material.dart';
 import 'package:intl/intl.dart';
-import 'package:mqtt_client/mqtt_client.dart';
+import 'package:mqtt5_client/mqtt5_client.dart';
 import 'package:shared_map/shared_map.dart';
 import 'package:stadtbote/main.dart';
 import 'package:stadtbote/protocoll_messages/accept_job_message.dart';
diff --git a/lib/tools/messages/publish_payload_message.dart b/lib/tools/messages/publish_payload_message.dart
index 7a5da19..9a12425 100644
--- a/lib/tools/messages/publish_payload_message.dart
+++ b/lib/tools/messages/publish_payload_message.dart
@@ -1,4 +1,4 @@
-import 'package:mqtt_client/mqtt_client.dart';
+import 'package:mqtt5_client/mqtt5_client.dart';
 
 class PublishPayloadMessage {
   final String topic;
diff --git a/lib/tools/mqtt_core.dart b/lib/tools/mqtt_core.dart
index 74f2ae2..cd5bcf4 100644
--- a/lib/tools/mqtt_core.dart
+++ b/lib/tools/mqtt_core.dart
@@ -6,8 +6,8 @@ import 'package:archive/archive.dart';
 import 'package:device_info_plus/device_info_plus.dart';
 import 'package:http/http.dart' as http;
 import 'package:isar/isar.dart';
-import 'package:mqtt_client/mqtt_client.dart';
-import 'package:mqtt_client/mqtt_server_client.dart';
+import 'package:mqtt5_client/mqtt5_client.dart';
+import 'package:mqtt5_client/mqtt5_server_client.dart';
 import 'package:stadtbote/model/enqueued_message.dart';
 import 'package:stadtbote/model/job.dart';
 import 'package:stadtbote/model/log_entry.dart';
@@ -93,6 +93,8 @@ class MqttCore {
     }
 
     connectionState = ConnectionStateEnum.notConnected;
+
+    _disconnectInProgress = false;
   }
 
   _connectToBroker() async {
@@ -165,7 +167,7 @@ class MqttCore {
   Future<void> _setupMqtt() async {
     Util.logInfo('_setupMqtt called');
 
-    _mqttClient!.updates?.listen((List<MqttReceivedMessage<MqttMessage>> messages) {
+    _mqttClient!.updates.listen((List<MqttReceivedMessage<MqttMessage>> messages) {
       for (var mqttMessage in messages) {
         try {
           final MqttPublishMessage message = mqttMessage.payload as MqttPublishMessage;
@@ -175,9 +177,9 @@ class MqttCore {
           var topic = topicArraySplited[6];
 
           Util.logInfo('message received\ntopic: $topic\n');
-          Util.logInfo("size in bytes: ${message.payload.message.length.toString()}");
+          Util.logInfo("size in bytes: ${message.payload.message!.length.toString()}");
 
-          var payload = utf8.decode(GZipDecoder().decodeBytes(message.payload.message));
+          var payload = utf8.decode(GZipDecoder().decodeBytes(message.payload.message!));
 
           Util.logInfo('$topic\nmessage: $payload');
 
@@ -235,7 +237,7 @@ class MqttCore {
 
       if (previousMqttSubscription != fromServerTopic) {
         Util.logInfo('topic changed -> unsubscribe from $previousMqttSubscription');
-        _mqttClient!.unsubscribe(previousMqttSubscription);
+        _mqttClient!.unsubscribeStringTopic(previousMqttSubscription);
       }
 
       _mqttClient!.subscribe(_fromServerTopic, MqttQos.exactlyOnce);
diff --git a/pubspec.lock b/pubspec.lock
index 93d7bbf..b8ee1b6 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -976,14 +976,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.0.5"
-  mqtt_client:
+  mqtt5_client:
     dependency: "direct main"
     description:
-      name: mqtt_client
-      sha256: "001861aba553eaf419aab60b7956227af47a9d1e1efe0d2fcb3957d3fc30d110"
+      name: mqtt5_client
+      sha256: d5d26200bc5f6d3a18cd7d007d5aa6bb04866150a8d42221ca5cecf2c807779c
       url: "https://pub.dev"
     source: hosted
-    version: "10.2.1"
+    version: "4.4.0"
   open_filex:
     dependency: "direct main"
     description:
diff --git a/pubspec.yaml b/pubspec.yaml
index 443eb68..64c2558 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -43,7 +43,7 @@ dependencies:
   open_filex: ^4.3.2
   path_provider: ^2.0.14
   split_view: ^3.2.1
-  mqtt_client: ^10.2.1
+  mqtt5_client: ^4.4.0
   isar_flutter_libs: ^3.1.0+1
   isar: ^3.1.0+1
   json_serializable: ^6.6.2