@AntiMS The experimental Halium 12 build has two reports of succesfull VoLTE - both originating and receiving (non US), and several one way only calls with or without audio. I personally have tried it with all three US networks. Verizon has trouble, but with both T-Mobile and AT&T networks you can receive calls with audio in both directions. However, making a call fails and the dialer hangs. Logs were sent to the porter, and it is suspected that this is an ipv6 vs ipv4 issue. We can help you more efficiently if you join the ubports NA Issues Telegram channel.