S6 Active Unlocked - going to T Mobile - Can i do Wireless calling?

[AC Question]

Switched over today.. cannot find how to enable wireless calling.
Can someone help?

 

[Tumultus]

You won't be able to! Only the devices sold by T-Mobile directly have the wireless calling. It is an app that's built into T-Mobile phones and even if you could find the APK, it won't work on your device because it also requires a lot of preinstalled services that non-T-Mobile devices don't have.