I bought a new phone last year from a parallel importer - a Sony Xperia 1 V, model XQ-DQ72. Today I got an email from 2degrees saying "Unfortunately, our records show your device doesn't support 4G calling."

"This may be the case if your device was parallel imported or purchased overseas. Even though these phones can connect to 4G networks, they may not be fully compatible. This can include, not supporting calls over 4G including emergency calls and/or they may be missing a feature called 700MHz (or Band 28)."

Well, according to this website at least, this model supports Band 28. In fact it appears to support every band in use by 2degrees.

Not only that, but in my phone's settings, "4G Calling" is enabled. When I call another phone (which definitely does have VoLTE), my phone stays on "4G" or "4G+" in the status bar (rather than reverting to "3G" as I've seen people say it would if it didn't support VoLTE). I even used the "Field Test Mode" menu (dialling *#*#4636#*#*) to set the preferred network type to 5G and 4G only ("NR/LTE"), and the call still worked just fine.

So, (third party) documentation online shows it supports the right band, and VoLTE does seem to work. Do I have anything to worry about? Why would 2degrees think otherwise?

The only thing I can think of is that either they have just sent me the email because my phone isn't on their list of officially supported phones, or because my phone isn't reporting explicitly that it supports 700MHz. I noticed that in the service menu it says "mFrequencyRange=UNKNOWN" in the "LTE physical channel configuration" info. Though surely 2D knows when it actually connects...

Is there anything more I can do to verify that it is indeed compatible with the 3G shutdown?