Description of feature:
It would be nice to have support for XEP-0369: Mediated Information eXchange (MIX).
A client supporting this appears to be Swift: https://swift.im/git/swift/log/
A feature request for Conversations exists: https://github.com/siacs/Conversations/issues/1764
The need for XEP-0369 is nicely described in its introduction section: https://xmpp.org/extensions/xep-0369.html#intro