Just asking. It was my impression you would only get the A1633/43 from ATT. The only one with the Band 30.
From PC Mag 9/10. Not sure if CDMA reference is correct. You could get the A1687/88 thru Apple. Just saying and not 100% sure. But, thought I saw that posted somewhere else on MR.
Alas, Not One iPhone for Everyone
There are still two models of the iPhone 6s, unfortunately. With the iPhone 6, the two models were "Sprint" and "everyone else." This time, it'll be "AT&T/T-Mobile" and "everybody but not totally AT&T."
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One model (numbered A1633 or A1634) has AT&T's new band 30, but lacks the CDMA radio needed to make calls on Verizon and Sprint. The other (A1687 or A1688) supports all four carriers, lacking only AT&T's Band 30. That model will eventually have slower performance on AT&T's network than the A1633 model, although it'll still work generally fine.
AT&T will sell the A1633/34 model. You'll be able to roam with that and switch it to T-Mobile if you want, but you wouldn't be able to switch to Sprint or Verizon. If you want a phone that could work on all four carriers, make sure to get an A1687/1688.