23-06-2018 10:17 AM
You can't w/out the EE firmware.
23-06-2018 11:14 AM
Thanks for posting on the community.
The Samsung Galaxy S6, S6+, S6 Edge, S6 Edge+ should support WiFi calling, when purchased direct or indirect.
However when purchased from a third party we cannot guarantee this will work.
If you need any help setting up WiFi Calling or experience any problems, please see the WiFi Calling Help page.