I have an ATT S7 Edge and was looking to switch to Tmobile. My S7E is unlocked with a Prepaid Tmobile sim in it now and all is working well (even VoLTE which I was shocked about). I'd like to have Tmobile software for wifi calling if it is at all possible. It seems as if VoLTE compatible so I figured the hardware was the same, just different software/basebands. I know Samsung is a nightmare with their carrier versions/locked bootloaders so I assume the chances of this being possible is unlikely, but I figured I should at least ask.