AT&T iPhone Owners Can Now Use WiFi Calling
T-Mobile Has Had Wi-Fi Calling Since at Least 2007...
at&t thinks they are so smart.
I think if the FCC had a problem with T-Mobile offering Wi-Fi calling they would have done something about it in the last ~8 years!!!
Once T-Mobile get 600 MHz spectrum at&t is going to have a hard time keeping customers unless they change their evil ways...