Seems like the Jodel Venture GmbH has changed its authentication mechanism.
The node-jodel client does not work any longer in my case.
The getAccessTokenForDevice method returns a response stating "Signed request expected" or simply Unauthorized
Seems like they added a new acess_token/refresh_token signing mechanism and an addition distinct_id object as stated in another github project at https://github.com/ppati000/jodelstats/blob/master/app/models/jodel_handler.rb
Greetings
André