The XMPP app on Freedombone has been improved a little by going to a single configuration file and also using the Debian package. Previously it was using a very hacky nightly version of Prosody, and the reasons for that are historical and no longer apply.
For most of the time that the Freedombone project has been going XMPP was being renovated and having all of the features which you would expect from a modern chat app added. Things like end-to-end security, working avatars and client state indication. So if you wanted to run Conversations on Android and have all of the server tests pass you needed to be compiling a recent version of Prosody from source. Debian moves at a glacial pace, but now the Debian packaged version is good enough.
The previous XMPP notifications system has also been replaced with sendxmpp, and this reduces the amount of maintenance needed.
XMPP may be old but it's still one of the most practical IM systems. An XMPP server can run even on the most minimal single board computer - unlike certain other chat systems that could be mentioned - and also supports the use of onion addresses. Many people are unaware that WhatsApp is really just an XMPP server with a proprietary client app and federation turned off.