diff --git a/Dockerfile b/Dockerfile
index 1050fd8..41a64d5 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM python:3.11-alpine3.18
+FROM python:3.12-alpine3.19
 
 RUN apk add --no-cache gammu-dev tzdata
 
diff --git a/sms2mqtt.py b/sms2mqtt.py
index 07cdeb0..e11d13c 100644
--- a/sms2mqtt.py
+++ b/sms2mqtt.py
@@ -254,7 +254,9 @@ def shutdown(signum=None, frame=None):
 
     logging.info('Gammu initialized')
 
-    client = mqtt.Client(mqttclientid)
+    # https://stackoverflow.com/a/77985329
+    # client = mqtt.Client(mqttclientid)
+    client = mqtt.Client(mqtt.CallbackAPIVersion.VERSION1, mqttclientid)
     client.username_pw_set(mqttuser, mqttpassword)
     client.on_connect = on_mqtt_connect
     client.on_disconnect = on_mqtt_disconnect