Gajim

Is a multiuser XMPP messenger client with support for OMEMO encryption, including sending of files and photos.

Scale to fit:

org.gajim.Gajim

Phone Compatibility:

5 of 5 Points

How to install:

sudo apt install gajim-omemo

Website:

Repo:

Tips & Tricks

Since version 1.4 in bookworm, there is only one single window. In order to fit in portrait mode, flip your phone once into landscape mode and back. If this still doesn't align, just make the texting area bigger by squeezing the contacts.

You can close Gajim window and still receive message information, as the demon still runs in background.

Known Issues:

Audio/Video calls untested so far (2020-08-18).