I have a KeyOne Limited Edition Black from India, a BBB100-7 in BlackBerry-speak. This just came out last month. It runs an identical Android OS to the silver KeyOne (BBB100-1). The only technical difference between the international black and the normal silver KeyOne is that it has more memory, and is dual-sim (needed for work reasons). BBB100-7 has the same band support as a BBB100-1. I put in my T-Mobile SIM and general calling just works, band 12 works, texting works, data works, etc. In most-every respect, it seems to be a fine T-Mobile citizen.
However, *unlike* the silver KeyOne, Wi-Fi Calling doesn't work. The KeyOne gets a REG90 error when attempting to sign in. Wi-Fi Calling and VoLTE are checked on, but IMS services don't show up as being enabled. I put this SIM in other devices, even those never formally supported by T-Mobile (e.g. BlackBerry Passport), and Wi-Fi Calling just works. No, it's not a matter of missing e911 (which is what the T-Mobile call center folks think it is until proven otherwise). It's a year old-SIM card, and supposedly an OTA update was pushed to it. I've confirmed the IMEI is "clean", not on any blacklist.
I'd really like to get Wi-Fi Calling working on this KeyOne, just like it works on older KeyOnes that do Wi-Fi Calling on T-Mobile just fine. Sure, I can use DIGITS, but that's not the same. Based on what I've read, the REG90 error means that *something* needs to happen at the T-Mobile end for this to work. I'd like to get my KeyOne's info added to whatever database T-Mobile uses to figure out how to provision IMS services. Heck, maybe this KeyOne is new and exotic enough that it hasn't caught up with the carriers.
HELP! Please advise! Thanks!