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.
Meshtastic can be encrypted and is LoRa based. Can easily hit nodes dozens of miles away with a good line of sight. It also relays messages across nodes to reach even further distances.