T-Mobile/AT&T new Voice over LTE rules

[ehmen]

T-Mobile and AT&T's representatives know nothing about this. Typical.
https://www.xda-developers.com/t-mobile-att-require-volte-phone-calls-shut-down-3g
https://www.digitaltrends.com/mobile/att-tmobile-verizon-3g-network-do-you-need-a-new-phone
https://www.digitaltrends.com/mobile/t-mobile-volte-support-phase-out

Will unlocked phones that have the VoLTE capability work after 01/2021 with T-Mobile and 02/2022 with AT&T?
(A Samsung representative explained to me that the VoLTE technology on unlocked devices might differ a bit from those on carrier branded devices, so there isn't a 100% guarantee that they'll work.)

Would anyone here know about this?

Thank you.

[ehmen]

Anyone?

[DavidR]

Anyone?

Given your comment that "T-Mobile and AT&T's representatives know nothing about this."

I rather doubt that users will have any details, other than that they will have gained from your links. 

Also this is essentially a USA issue, non-US users will have little interest/knowledge unless it migrates and applies to their country, T-Mobile is/was also available in the UK, but the network infrastructure re 3G, 4G and 5G.  But Merged with Orange UK bought by
EE, which is now owned by BT (British Telecom).  I used to be with Orange, then EE and now BT.

The UK is already committed to shutting down 3G
https://www.pocket-lint.com/phones/news/vodafone/148297-vodafone-we-ll-switch-off-3g-in-the-next-two-to-three-years
https://www.lightreading.com/mobile/3g-hspa/bt-aims-to-switch-off-3g-by-2022/d/d-id/743940

And then there is 2G
https://www.techradar.com/uk/news/2g-may-not-be-switched-off-in-the-uk-for-another-decade

Some of these are a year or older, so it has been an ongoing consideration for some time.