Looking for a stable Crypto Messenger

[wibble]

I don't think there's a reason briar-gtk wouldn't be able to work on mobian, but you'd need to compile it yourself as their current packages for the briar-headless dependency are amd64 only. They're working on getting it included in debian, at which point it would become available for mobian as I understand it, but it's not there yet. I suppose you could ask them to compile aarch64 packages.

https://code.briarproject.org/briar/briar-gtk
https://code.briarproject.org/briar/bria.../issues/72
https://media.dorfbrunnen.eu/briar/debs/briar-headless/