I have a Galaxy S7 edge that was originally built for Orange France and have found that it does not support WIFI Calling. After much research with both Samsung and Three the reason appears to be that the firmware supplied to Orange France does not support this function. I am led to believe that 3UK or may be BTU firmware could resolve this issue. Is it possible to update the firmware and if so how. Any other thoughts on resolving this issue would be very much appreciated.
I'd suggest to go over to xda-developers.com to learn more.
Disclaimer 》 Using a Custom Rom can bring about an unstable phone or it may not work properly if the process glitches or the wrong Rom is used. A person takes full responsibility if they perform this process and do so at their own informed decision. Samsung would levy a charge to put this right.