The “app”, as you call it, only subscribes to the services provided.

And?

any features you described are on the server side (as to your post title)

None of the features I described (the interface) are on the server (the interface).

You are asking about the server

I am not. Again, please refer to the first three words in the body of post. In general, I urge you to read posts before you respond to them.

Why else would you post in “self-HOSTED”. Applications aren’t hosted.

it’s in regards to a self-hosted xmpp server.