In the hopes of clarifying a bit of confusion and concern I see in the comments, I’ve reached out to T-Mobile to confirm that there will be no Wi-Fi calling on the Nexus 4. Now, odds are greatly in favor of this not being a T-Mobile decision anyway as a Nexus device generally doesn’t receive any carrier input. Therefore, T-Mobile likely had zero input in the manufacturing of the device and couldn’t request the inclusion of this feature. Hopefully, this won’t deter anyone from picking up the Nexus 4, but I thought you all should have a definitive answer.