Signal is the world’s most widely used truly private messaging app, and our cryptographic technologies provide extra layers of privacy beyond the Signal app itself. Since launching in 2013, the Signal Protocol—our end-to-end encryption technology—has become the de facto standard for private commu...
As I wrote elsewhere in this thread, XMPP would be my preference. It just works. In fact that’s what the other messengers (at facebook, Google, …) already use, but chose to put behind a walled-garden.
What matters is that whatever comes next (or, from the past in the case of XMPP) is federated, so no single organization has a single-handed control/monopoly over the network. Matrix and SimpleX are federated alternatives to XMPP, but I don’t see Matrix stabilizing any time soon, and SimpleX just isn’t ready yet. XMPP can offer you today an experience that’s comparable to WhatsApp/Signal/Telegram/…
What’s the issue with Matrix? I’ve tried both Matrix and XMPP but stuck with Matrix because it just works. XMPP is also good but it lacks a good Android client (The available clients look very outdated, and honestly, pretty ugly). It’s also kinda hard to know if your client or server even supports all the extensions that are needed.