Will ATT iphone work with T-mobile's Wifi calling?

[ACG12]

Seriously considering dumping ATT and switching over to T-mobile, but wanted to confirm this feature will work. Can anyone who's switched confirm that wifi calling will work if I unlock my ATT phone and switch it over?

 

[Closingracer]

Yes it's the same phone model. Apple sells two models in the United States.... One for Verizon , AT&T and T-mobile and one for sprint. The sprint one can work on any network given it is unlocked.

 

[Applejuiced]

Yes, as long as your AT&T iphone is unlocked.
Wifi calling and every Tmobile feature will work fine.

 

[patt2k]

I am using Verizon model on T-mobile. Works fine. Verizon models come sim unlocked out of the box.

 

[imlynxy]

When you swap your sim cards, t-mo sends a carrier update on your phone, just accept it and you will have all the features there. There is a problem sometimes with non-att iphones to obtain volte from Att, but this is another story.

 

[rpetunderclass]

The sprint one can work on any network given it is unlocked.

Can confirm, I have tried a Verizon, AT&T, & T-Mobile sim and got let/4g/3g volte/wifi calling with no problems.