So some time ago @sam_uk proposed using riot.im instead of signal for the ‘internet’ messaging gateway. I just spent a bit of time to look into this and I think it is a really good idea. This will be implemented after 1.0 and it will be built on top of the “mesh to MQTT gateway” and a "MQTT to riot.im bridge (to use the riot dev’s terminology).
If you are interested in this topic, the current rough plan is here:
And by the magic of discourse linking any comments you make in this thread will be recorded with that bug.