I totally get your frustrations, and they do get feedback from the mobile chat team and the forums.
But I don’t see how they can say what other handsets will work with certainty unless it comes from them with the correct firmware. An example of which is on this thread, someone was able to get his pixel working with the EE EVR firmware, and another user who put that same variant on his pixel couldn’t.
If as you say, this was a way to get people to upgrade handsets then they would be offering deals not pac codes.
I really don't think this is firmware dependant. Any firmware that supports VoLTE should work. So generic samsung firmware with VoLTE support should work just as well as EVR firmware with VoLTE support.
I say this as my Xiaomi (Redmi Note 4 Global) is imported from China and running custom EU focused Firmware (xiaomi.eu) and it works perfectly fine with VoLTE, no VoWIFI for me as Xiaomi don't support that currently.
It is to do with how a handset is shipped and what it is flashed with.
Many networks have their own variant of firmware and tweaks, with EE they use EVR. I’m sure other networks also use their own variant.
When a customer brings their own handset to BT Mobile it could be any variation of firmware installed by a previous network or have country restriction, and some versions have hidden menus. BT’s update doesn’t enable the the service or alter the firmware on a handset. So that handset has to be the correct firmware to the requirements of the network.
Whist some generic firmware may work it, is easy to say may work or they dont support it to eliminate any liability if customers chose to change settings and firmware
BT’s “may work” is a list of some handsets that may work and many more may well work. What they are saying is they can’t guarantee if the service will work and how it may perform.
I am unsure of the current state of my sim. Last week on the My BT > My Mobile webpage there was a section titled "Phone and SIM" which said "4G Calling Device Unknown" and "WI-FI Calling Device Unknown". That same section now says "4G Calling Not compatible" and "WI-FI Calling Not compatible". There is also now an extra section near the top which says in a bigger font "You dont have 4G Calling" and "You dont have WI-FI Calling".
I have a family sim and the other sims on the account dont have this changed and new information. Wifi calling is still not shown as a menu option on my phone (zperia z5 compact running android 7.1.1 which according to Sony does support wifi calling) and so of course wifi calling is innaccessible.
I dont have access to a phone that has definately been working with wifi calling so does anyone know if there is a way to tell if a sim has been updated for wifi calling without moving the sim to a BT sold S9? Somewhere on the My BT webpage that can say for sure maybe?
The phone and sim section showing the device as unknown is normally corrected by placing the sim in another handset if you have one or when it’s refreshed.
Thw wifi calling and 4G calling section only normally shows you have it when your sim is in a compatable phone and the sim has been enabled
In regards to the status of sims, it’s a gradual roll out so some SIM cards get updated faster than others. But you can check the status of your sim by contacting the mobile chat team.
I also have a Xiaomi Redmi Note 4 running the latest weekly rom from xiaomi.eu. However my VoLTE isn't working, are you running a stable or weekly rom build? And which version?
I also have a Redmi Note 4 Global running the latest weekly build from xiaomi.eu but my 4G VoLTE isn't working. Are you running a weekly or stable rom build? And which version?
Weekly, I only joined BT on 20th March, running versions 8.3.15 & 8.3.22 and worked fine on both. Do you have it as an option in settings for the SIM? If not dial *#*#86583#*#* and you just get a pop up about it being enabled, reboot your phone and check settings again and the toggle should be there (this should work on official global roms as well). I've not tried the latest rom 8.3.29 but imagine it would work still, I can update and test if the above dialer code doesn't work for you (if not I'll just update this Friday).