[SamWhited]

As opposed to what that doesn't lock you in? I'd be curious to see how they do it. With an XMPP compatible account you could at least host with your own domain (by running your own server or using a hosted service like https://account.conversations.im/domain/), and then moving isn't too bad. If you fall under GDPR regulations you can presumably ask for a copy of your data now too, and then hand that to whatever your new provider is if you move. That being said, people don't move servers that often, so it doesn't seem like a huge deal either way to me. It could certainly be easier though. Maybe someone should write a spec for that or update one of the older ones?

[tehabe]

Weirdly enough, services like WhatsApp, Signal, or Telegram are more portable. Because the identifier is not owned by the service but is provided by s.o. else. It is essentially a decentralised social graph in the address book of your phone. I'm aware of the caveats though.