Support matrix!! It already has international support, just needs to be a bit better with stickers and qol stuff. I’ve been using it for years. It’s nice to know I don’t have to worry about my privacy at all with chat rooms that can continue on without the original server.
Technically all certificates are pinned, especially with public CAs, most OS package the latest CA certs which will all go out of style within 10 years or so. You can see this by loading up any old distro or defunct version of windows.