So yeah like I was saying. TMobile says it does....
Not any more, and the original "statement" was in error.
They did, in a cut-and-pasted boilerplate support document that some one apparently forgot to cut out before posting it. An error that has since been corrected.
Support: Connectivity & data: Google Nexus 4
Or do you have another source that is now saying it does?
Sorry, I wish it did, too. All the carriers have somewhat spotty coverage in my house and I'd GLADLY PAY for seamless WiFi calling.
But it ain't there. That doesn't mean that someone (even T-Mobile) won't add it later - I could easily see T-Mo downloading the firmware and adding it if the phone is popular enough, but then all your firmware updates would have to go through T-Mo on their way to you, so at some point when T-Mobile gives up on doing this you'll end up either living with older firmware or going back to Google OTA and losing WiFi calling.