I've installed Jami both on my Librem 13 (Linux, debian-based) and my fairphone 2, but it's not yet working. When I call myself on the other device (tried it in both directions), the connection is breaking down ("missed outgoing call"). I can see on the fairphone that the window for the call opens, but it looks a bit such as frozen, and I cannot click anything (e.g. mike). Chat works. Any idea how I could make it work?