I am not using this setup on a Librem 5, but it seems like a few people are interested in using jmp.chat for texting/calling on the L5.
I have Gajim set up and working for calls, texts, and media messages. However, I am not able to find any documentation on whether jmp.chat works for group messages. Has anyone successfully set that up?
This response has you covered (it’s from the lead dev), since the feature is in alpha if I’d recommend joining their support group if you need further details.
A more reliable form of communication
On the group chat question, to start a group chat it’s as was said: you use the Jabber ID of +1...,+1...,+1...@cheogram.com (numbers separately by commas) for the contact. To answer another sub-question, if you sort them in increasing numeric order, then replies will come back on the same Jabber ID.