I understand it has replaced UMA however some handsets (i presume BlackBerry) still support UMA.
I guess my main questions are
1 - Is Wi-Fi calling an App - what's the technology if it isn't UMA
2 - With Wi-Fi calling (without UMA) Will the call drop if switching between Wi-Fi and cellular and vice versa.
The Wi-Fi Calling webpage contains the following small print "Except for UMA devices, device will not transition between Wi-Fi and the wireless network."
It leads me to believe there is no seamless hand over to the cellular network
The Nokia Lumia 512 - offers 3 settings - Wi-Fi preferred, Cellular Preferred and Wi-Fi Only. Is there any hand over in the Wi-Fi preferred or Cellular preferred scenario - will the call drop if a Wi-Fi preferred call looses Wi-Fi but there is cellular coverage available ?
One last related question - Does T-Mobile offer public Wi-Fi like AT&T ?