We all know Signal, Matrix, Telegram, SimpleX, etc… But if you can’t access the internet you can’t communicate. Pretty logic. But would it be possible, at least theoretically, to create an app that permits to message people even if the internet goes down?
It might be a dumb question I really have no idea to be honest.
yggmail is a fairly obscure and experimental take on email on a mesh network: https://github.com/neilalexander/yggmail