diff --git a/data/config/mosquitto/openwb_local.conf b/data/config/mosquitto/openwb_local.conf
index f540b3dcf1..e9acb2edc3 100644
--- a/data/config/mosquitto/openwb_local.conf
+++ b/data/config/mosquitto/openwb_local.conf
@@ -1,4 +1,4 @@
-# openwb-version:19
+# openwb-version:20
 listener 1886 localhost
 allow_anonymous true
 
@@ -33,8 +33,6 @@ topic openWB/internal_chargepoint/# out 2
 topic openWB/io/# out 2
 topic openWB/internal_io/# out 2
 
-topic openWB/mqtt/# both 2
-
 topic openWB/pv/config/configured out 2
 topic openWB/pv/get/# out 2
 topic openWB/pv/+/config/# out 2
diff --git a/packages/helpermodules/pub.py b/packages/helpermodules/pub.py
index 1f5f15c2b2..fb6c0017b5 100644
--- a/packages/helpermodules/pub.py
+++ b/packages/helpermodules/pub.py
@@ -45,6 +45,8 @@ def pub_single(topic, payload, hostname="localhost", port=1883, no_json=False, r
     no_json: bool
         Kompatibilität mit ISSS, die ramdisk verwenden.
     """
+    if payload == "":
+        no_json = True
     if no_json:
         publish.single(topic, payload, hostname=hostname, port=port, retain=retain)
     else:
diff --git a/packages/helpermodules/update_config.py b/packages/helpermodules/update_config.py
index 40daa6a85b..7204994976 100644
--- a/packages/helpermodules/update_config.py
+++ b/packages/helpermodules/update_config.py
@@ -28,7 +28,7 @@
 from helpermodules.measurement_logging.process_log import get_default_charge_log_columns, get_totals
 from helpermodules.measurement_logging.write_log import get_names
 from helpermodules.messaging import MessageType, pub_system_message
-from helpermodules.pub import Pub
+from helpermodules.pub import Pub, pub_single
 from helpermodules.utils.json_file_handler import write_and_check
 from helpermodules.utils.run_command import run_command
 from helpermodules.utils.topic_parser import decode_payload, get_index, get_second_index
@@ -56,7 +56,7 @@
 
 class UpdateConfig:
 
-    DATASTORE_VERSION = 89
+    DATASTORE_VERSION = 90
 
     valid_topic = [
         "^openWB/bat/config/bat_control_permitted$",
@@ -2348,3 +2348,21 @@ def upgrade_datastore_88(self) -> None:
         pub_system_message({}, "Es gibt ein neues Theme: das Koala-Theme! Smarthpone-optimiert und mit "
                            "Energiefluss-Diagramm & Karten-Ansicht der Ladepunkte", MessageType.INFO)
         self.__update_topic("openWB/system/datastore_version", 89)
+
+    def upgrade_datastore_89(self) -> None:
+        def on_connect(client, userdata, flags, rc):
+            client.subscribe("openWB/mqtt/#")
+
+        def on_message(client, userdata, message):
+            topics_to_delete.append(message.topic)
+
+        topics_to_delete = []
+        BrokerClient("deleteMqttDeviceExternalBroker",
+                     on_connect,
+                     on_message,
+                     host="localhost",
+                     port=1883).start_finite_loop()
+        for topic in topics_to_delete:
+            log.debug(f"Lösche MQTT-Device-Topic {topic} auf dem externen Broker")
+            pub_single(topic, "", port=1884)
+        self.__update_topic("openWB/system/datastore_version", 90)