I don't have a link handy, but this is also coming soon to Verizon. My little throw-away phone will soon have to be thrown away. Probably important to triple check that this phone isn't used for 2FA anywhere. I believe January according to their support team, but don't quote me on that.
See above where I asked them during each interaction (usually more than once) whether the device was supported on their network. Also note that they replaced my device. Why would they send me a device that would no longer work on their network three weeks later?
Also, after swapping SIMs back and forth with my iPad, the ZTE 64 is once again working. I believe that TM is running a script that checks when the device first joined the network, and how long it's been since the device negotiated a 4G LTE connection. If joined after 8/1/2021 and no LTE for a week, the device is banned. Swapping the SIM into a different (LTE capable) device resets the one week timer.
As an aside, I can see that some of TM's cell sites are still advertising 2G service. Press releases from last year said they would support 2G/3G service until December 2022. Now the press releases are saying they will shut those down at the end of this month.
Also, the ZTE 64 is a 4G LTE device, but even though I bought it from T-Mobile, they are claiming that it will not use LTE on their network. Apparently the frequency bands for their LTE are not compatible with the device. This would not bother me so much if I had not bought the device from them, but I did, and they should support it.
Yesterday I ordered a new Netgear Nighthawk MR5200 (5G, Unlocked). They are pricey, but I already have a MR1100 (4G) and I believe it's the best hotspot I've ever used. They say I'll get the new one on Thursday. Hoping that's true.