First some background: My wife has a Nexus 5X. We both previously had Nexus 5's running on CDMA. I switched to GSM a few weeks before my Nexus 6P came. My wife has only used her GSM SIM in her Nexus 5X.
In the Device Settings I cannot enable Wifi calling for her device. However, I enabled Wifi calling when I had my Nexus 5 and it has stayed active even though I have switched to the 6P, though my phone still shows as a Nexus 5 on Ting's website.
I'm assuming this is just a situation where the 5X hasn't been flagged, I'd guess my 6P only has working WiFi calling because the system still thinks I'm on a Nexus 5. When will these phones be properly flagged as supporting Wifi calling?