For those who need WiFi Calling on T-Mobile and are frustrated that it's not activated in Moto X Pure MM Android 6, please read the following: I recently visited a friend out of state who's ground floor level apartment in a large building gets terrible T-Mobile reception. She relies on WiFi Calling on a Samsung Galaxy S5 but gets unreliable service, dropped calls, etc. We went to a T-Mobile store and she got the free CellSpot--free with a $25 refundable deposit. I installed it for her in her apartment--easy set up. Once activated, it runs its own set-up for about 45 minutes. Then both she on her GS5 and I on my Moto X Pure MM received 4 bar, high speed LTE. From zero reception to perfect reception, once the CellSpot was installed and activated. She reports perfect results since--no more dropped calls--and crystal clear voice quality. BTW, else where in her building my Moto X picked up T-Mobile band 12. I highly recommend the CellSpot. I don't use it myself in my home because I get great T-Mobile reception. Also note, she has WiFi calling now turned off--she is only using the CellSpot.