WeAreAllOne , 3 months ago

Many years ago I used XMPP with Prosody and it was ok.

• You can setup some retention time for attachments and history depending on the space you have.
• There are clients for multiple platforms but not very much advanced vs competition.
• Security is good with omemo protocol. In so e clients you have to turn it on since it's not by default.
• Audio video calls on one to one is good as long as you setup stun coturn server. Android to iOS calls still in progress.
• Check out Snikket for an all in one solution.

You might want to also consider Matrix (dendrite option ?) for your needs.