The S7 EDGE Wi-Fi calling will work no matter where you bought the handset from according to EE. EE Wi-Fi Calling phones
I'm using my BT SIM in a Samsung Galaxy A5 2017. The Wi-Fi calling option is there as it VoLTE but both do nothing.
Ahh that must be reasonably new then as this was nowhere to be seen, This was not on their site when i was ordering my phone aswell as i called EE and Carphone Warehouse in which both cases they said i needed to purchase direct from EE not Carphone warehouse or Wi-Fi calling will not work.
I have just joined BT for my landline and broadband. My wife and I would also taken out the family sim option if wi-fi calling had been available.
That would be awesome. I was on EE but recently changed to BT thinking it would work the same way with Wifi Calling. Man, i hope this is true because my signal struggles where I live as there is only one cell site that my carrier is using in this particular part of Holmfirth. It was the same situation with EE hence why both me and my partner both had an old Blackberry with EE sim's using Wifi calling. We then both switched to Samsung s6 with EE but mine got broken beyond repair (Fast Moving Train Long Story).
I am now using BT in my backup phone. I know for a fact that if they add this feature many people will switch to them especially those who have the Internet from BT and home phone because you can then manage all coms accounts in the same place and have one provider etc. I like that idea myself.