Sharing my experience of getting VoLte to work:
For reference, I would consider myself a general user of linux. Not an expert. But I do like to tinker with stuff.
I signed up for PureTalk (AT&T backbone) and got a SIM from them. They said I was good to go when I looked up my IMEI on their page.
I was admittedly under-educated in the phasing out of the g’s when I received my L5; not to mention VoLte vs. dropping to 3g for connection. Were I aware before, I wouldn’t have been too surprised that voice didn’t work on receipt. But now, after reading about the carrier phase out, this entire post, and quite a few other pages, I have some general knowledge.
So after a few beers, I convinced myself it was a good idea to try to turn on VoLTE using the “screen” command in terminal. I went through the steps, cycled the modem, attempted a call, and it worked. I had the phone set to 4G only, so I know it didn’t switch over to something else. The next morning I called my phone from anther, and it rang and picked up.
So here’s the short version of the data point I acquired:
VoLte worked immediately on PureTalk (AT&T MVNO) after enabling it through the terminal commands. I didn’t even have to cycle the device power - just the modem.
And the only hair-raising part was typing in the terminal commands just right on the phone keyboard with my fat fingers. Also learned in the process that using the backspace key in the screen command doesn’t really echo back like one would hope… duh.