Conversations.im has made great progress in making XMPP usable on mobile devices, although its services don't seem ready for public adoption quite yet. There are very few XMPP servers which support the XEPs Conversations does so while federation is theoretically possible, it is not yet a reality.
The new extensions are all public and supported by the two main server implementations, prosody and ejabberd. You can nicely ask your server operator to enable them.
