Has Mosquitto also updated itself? Maybe check this: Updating Mosquitto MQTT from 1.x to v2.0+
If this isn’t the issue you’re going to have to provide some more info on how you installed/upgraded openHAB, and how you installed Mosquitto originally.
Has Mosquitto also updated itself? Maybe check this: Updating Mosquitto MQTT from 1.x to v2.0+
If this isn’t the issue you’re going to have to provide some more info on how you installed/upgraded openHAB, and how you installed Mosquitto originally.