Keep in mind Matrix is a protocol for messaging just like email is a protocol for mail. There's more than one client and Element just so happens to be the most popular one. A really good runner-up would be FluffyChat. Then there's Cinny. Source: over 1 year ago

That's actually almost a ripoff of FluffyChat with the pull-up server list from Element's Android app. And given Matrix is trying to mimic the semantics of Discord servers with spaces, I don't even like those layouts. Gross. Source: over 1 year ago

There is a package I wanted to use fluffychat (Matrix Client) you can only get it from flathub and snap (officially) there is an aur package for arch (unofficial). This is just an example. There was also some other package that I no-longer use that had a similar case. More will become like this that's for sure. I don't like this future, it sucks. Source: over 1 year ago

@Hamuko I have been on matrix several years, and lately I've been really liking Schildi Chat [https://schildi.chat]. Also, many other users that I know really like Fluffy Chat [https://fluffychat.im/]. In any case, there are several more options nowadays. - Source: Hacker News / over 1 year ago

Then I've found FluffyChat, and it seems to working just fine; and has a Linux version too. Source: over 1 year ago

Well I can tell you that any SIP program can do this, one that comes to mind is Linphone. But you do need a provider. Almost all providers deal with UDP. You might be able to find one that transmits over tcp but that’ll be a very small list. TCP isn’t reliable for VoIP, for media anyway. At best you’ll find one that encrypts the signaling over TLS, which is TCP. But audio, even if encrypted too, is done over UDP.... Source: over 1 year ago

Does Linphone (https://linphone.org/) not meet that need of cross platform (website claims versions for all major OS'es) and open source (https://gitlab.linphone.org/BC/public/linphone-desktop)? - Source: Hacker News / over 1 year ago

Similarly, you can use any SIP (VoIP) provider (e.g. VOIPo Cloud), and configure the SIP account details in your native phone app. This way you will also be able to use a SIP softphone on your computer (e.g. LinPhone on Linux or Telephone on Mac), or even a real SIP phone in your home. Depending on your SIP plan you may or may not be able to make international calls this way. Source: over 2 years ago

I heard on RFD Fonus is using linphone.org to code their service. Source: almost 3 years ago