most XMPP clients support XEP-0363 (HTTP File Upload) nowadays. Jitsi still
doesn’t. Therefore we’d liked to implement that feature for Jitsi smack4-2 to
make it possible to send files to multiple recipients.
This would definitely be a good addition to Jitsi! Looking forward to your pull requests.
The smack4-2 branch isn't tested very well yet. We're currently preparing a 2.12 release based on master. The smack4-2 will then be merged into master so that the nightly channel is based on it and people can start using it and reporting bugs.
Kind regards Moritz and Daniel