I’m really hoping OMEMO makes it into Openfire (XMPP Server) and Adium (XMPP Client) sooner rather than later, we current use OTR but OMEMO is objectively superior in every way I can see.
In general, servers should have nothing to do with end-to-end encryption, except for not actively breaking it.
OMEMO in particular uses:
- Personal Eventing Protocol (PEP, XEP-0163) to transport key material; and
- core RFC3920/RFC6120 XMPP protocol to transport encrypted messages.
Both of which are already supported by Openfire [see JM-1122]. So, as far as I can tell, Openfire is fully capable of delivering OMEMO messages right now.