> really open source

Yeah, except that pesky server, right.

To be fair, Signal hadn't released source code for their server for over a year before today ;P.

True, which is why you should have switched to Matrix.

Let's stop making the same mistake over and over again. It is centralized, not federated, and therefore Threema is likely to suffer the same fate.

DeltaChat, it's encrypted email that present itself as a chat. You can use your own smtp, or use a existing one. It only needs to be able to create a folder locally and use GPG. ( the smtp, the client app has passed the mom test of installation )

Experience is below signal, but decent.

I would like to do the same, but most of my friends aren't even on Signal. There is no chance in hell that they buy a messenger.

Except the server it seems? I only see the various clients on github.

Like signal, their server code on github is not what they are running.

With signal, there is at least the occosional server code dump. The threema server is closed source.

And no E2EE!

That is absolutely false: https://threema.ch/en/