I was under the impression that 4S and above would support wifi calling if you're with T-mobile. I have an iPhone 5, Tmobile carrier version 17.1, but no option to turn on wifi calling. Updated to iOS8 this morning. Can anyone confirm? Pretty upset that there is actually no wifi calling on the iphone 5. Really heavily considering to go for the iphone 6 now if there isn't any wifi calling on the 5 as they had originally promised.