Hi @MZ-BER,
today my MM showed that there is an update of the MMM-PublicTransportBerlin module. Hence a git pull and an npm install solved the problem. 
Many thanks to @KristjanESPERANTO, @deg0nz and all who work so diligently in the background to keep the MM running!
May the code be with you
-kai
Hi @bhepler,
thank you very much for your answer. I appreciate that very much.
Please excuse my late response - time flies by…
Meanwhile I discovered your new WeasleyClock release and your walkthrough for setting up a mosquitto server.
Thank you so much!!! 
Today I deleted and re-installed the WeasleyClock on my magic mirror and followed your mosquitto guide and everything works so fine now! I have both a WeasleyClock and my own MQTT server with password and TLS. Wow!
That’s entirely thanks to you. 
Thank you very much again for all you effort!
May the code be with you
-kai