De-register push notification for specific user

Hi community,
is there a way to de-register push notification for an user within openfire?
Situation:
User changed to a different app.
However, the push notifiction plugin keeps sending the notification to the api server of the old app what is not in use any more. (entries to see in log files )
To the new api server instead are not being sent any notification. (nothing in the log files to see)
Both connection to the old api and new api server are visible in Sessions → Server Sessions
So how can I change this?

Regards,
Andre