Thank you for your explanation. Ah, okay, I see. It is server, Android and iOS App, so it seem to be the same 'environment' for all usecases. ...
I'm happy with my ejabberd server.
Is it possible to use iOS Snikket with ejabberd (by entering server adress, username and password)?
So it possibly could be an extension for my usecase (ejabberd, with Conversations via F-Droid and Dino).