PSA: Apple’s iPhone 6s CDMA spec change makes AT&T’s model its best worldphone


When Apple introduced the iPhone 6s at its September 9th special event, it billed the new model as the “best phone for traveling around the world,” thanks largely to support for “23 bands of LTE wireless networking.” But that day, the new iPhone’s tech specs page told a more complex story: Apple advertised a seemingly U.S. and Puerto Rico-specific A1633 iPhone 6s with 23 LTE bands (including AT&T’s exclusive band 30) but no CDMA support, while Sprint, T-Mobile, Verizon, and every international carrier outside China got an A1688 iPhone 6s with 22 LTE bands and CDMA support. Clearly, the “best phone for traveling around the world” would be the international A1688 version, right?


Wrong. This week, Apple started selling a SIM-free, unlocked iPhone that works with “any supported carrier worldwide, such as AT&T, T-Mobile, Verizon, or Sprint in the United States.” Hidden inside a text link titled “Learn more about the SIM-free iPhone,” Apple notes that the SIM-free iPhone 6s is model A1633 — the AT&T version, not the one sold internationally. How could this make sense?…


simfreeiphone’s Wayback Machine confirms that Apple changed the iPhone 6s tech specs page (shown below) at some point after the September 9th event to note that the A1633 model actually does have CDMA support after all. On the A1633 (and iPhone 6s Plus model A1634), the line noting CDMA EV-DO Rev. A now appears below the UMTS line, with the same supported frequencies as the A1687 and A1688 models below.


In other words, if you bought a Verizon, T-Mobile, or Sprint iPhone 6s thinking that you were getting Apple’s best worldphone, too bad. The updated tech specs page suggests AT&T’s version has all the same features, plus an extra LTE band for improved performance on AT&T’s network, which means the A1633 should deliver optimal performance on any U.S. or international carrier outside of China. Also interesting: Apple’s pages differentiate between A1688 (GSM) and A1688 (CDMA), hinting that there may be software or other locks on the Verizon/Sprint and T-Mobile/international GSM phones, while no such distinction is made for the A1633.


Apple’s international customers may be in for a different surprise. The FAQ question “can I use my iPhone outside my home country?” on Apple’s UK iPhone 6s pages suggests that international SIM-free/unlocked iPhone 6s customers may be getting a GSM-only version of the A1687, which mightn’t work on CDMA networks. “iPhone is enabled to work on networks using GSM around the world,” says the FAQ. “Because the iPhone sold by is unlocked, you can purchase a SIM card and service from a local carrier at your destination.”

Who will be affected by this? If you’re a Verizon, T-Mobile, or Sprint customer who bought an iPhone 6s or 6s Plus with thoughts of possibly switching to AT&T, you don’t have the best phone to take advantage of AT&T’s network — and may want to get a SIM-free phone instead. But if you’re an AT&T customer who worried about using your phone on a CDMA network, you may be in better shape when switching carriers than you’d originally expected.

Update: Apple has confirmed to Macworld that the A1633 and A1687 iPhones are identical to one another except for the A1633’s added support for AT&T’s LTE band 30 — currently only available in limited U.S. markets, but possibly coming to international markets in the future. As Macworld notes, Apple declined to comment on why it would “manufacture two sets of ostensibly almost identical phones that they sell at the same price,” but the conclusion is clear: if you want a iPhone 6s with the broadest possible network support, AT&T’s version — unlocked — is Apple’s best option.

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  1. iSRS - 7 years ago

    Keep in mind, Verizon is not allowed to sell locked phones at this time.

  2. Shan - 7 years ago

    I have seen CDMA compatibility listed under A1633 since September 12th (pre-order date). I don’t think that this is a surprise ‘news’.

    • Jeremy Horwitz - 7 years ago

      Definitely surprising to some people. Hard to know when it was changed, but it was changed after the event and the initial swirl of publicity.

      • kpom1 - 7 years ago

        It was changed a day or two after the announcement. PCMag editor Sascha Segan noticed it.

  3. nickdillon91 - 7 years ago

    So just to confirm. I purchased a T-Mobile iPhone 6S out right on Apple’s website. If I chose, I could activate that on Verizon in the future correct? Or do I need to return it for the SIM Free model?

    • Jeremy Horwitz - 7 years ago

      I just put a Verizon SIM into my full price-purchased T-Mobile iPhone 6s Plus, and it showed up as the carrier without a complaint about network compatibility. So I think the answer is “you’re fine.”

    • kpom1 - 7 years ago

      It should be that simple, but because the T-Mobile version doesn’t show up on Verizon’s database, the sales person will tell you it doesn’t work and won’t open up a new account. But they will if you buy the SIM-Free version. If you are still in your return window and you might switch to Verizon, I’d just return it. Do a backup through iTunes (and sync music, apps, etc.) and that saves some of the hassle of replacing a phone.

      • nateo200 - 7 years ago

        Old post but I thought I’d throw in my experience….I swapped between T-Mobile and Verizon when I had a 5c and I went to the Verizon store to get a phone for my sister. The lady looked up my phone and it said it was in the data base as “not supported” even though I bought it through Verizon. Lady FREAKED out, she accused me of lying saying I couldn’t have possibly had a Verizon iPhone 5c and be using it on both carriers anytime I wanted and then threatened me by saying she was going to “report” this to Verizon and Apple…apparently she didn’t get the FCC rules regarding SIM locking and Verizon’s Band 13 purchase. I did the same thing with my iPhone 6 for a bit. Anyways I don’t understand why Apple feels the need to have all these seperate models, every year since the 5S it seams that they find a way to screw certain iPhone models and customers out of international LTE bands…case in point is the new iPhone SE which lacks Band 28 and Band 7 on the Verizon model but supports Band 12? Meanwhile the other models support all the TD-LTE bands plus B28 and B7. Its all just a mess…if they really cared about making a truly global phone every phone would have the essential bands + all the extras. Seams it would be more expensive to make to models of a phone where one just has a few less bands (likely disabled in the firmware)

  4. telecastle - 7 years ago

    Are AT&T iPhone 6s and iPhone 6s Plus versions come locked? I’m now confused about all different ways to get a new iPhone from a carrier. It used to be much simpler – if you get an iPhone from a carrier, you get it subsidized by the carrier and most carries (except for Verizon) locked the iPhones for the duration of the contract. Now there are so many different ways to get an iPhone from a carrier that there are probably some ways to get an unlocked phone directly from AT&T (for example). Please shed some light on this.

    • I bought an At&t 6s plus full price and after the initial set up it notified me that the phone was now unlocked. I verified this with a SIM card from a Mexican provider and it was indeed unlocked. Same thing happened when I bough the 6 plus.

    • kpom1 - 7 years ago

      As long as you paid full price from Apple it is automatically unlocked.You don’t need to do anything. That goes for the Sprint, T-Mobile, and Verizon models (actually, all Verizon LTE phones, even subsidized phones, are unlocked). If you buy a phone directly from T-Mobile, Sprint, or AT&T, you need to request an unlock. AT&T will do so right away if you paid full price. T-Mobile and Sprint require you to have service from them for a period of time. So the easiest way is just to buy it directly from Apple.

  5. Chad Dutcher - 7 years ago

    The only difference is band 30 and AT&T is JUST beginning to it roll out (and only in a handful of markets). For all intents and purposes, they’re identical phones.

  6. The Apple iPhone LTE site now says that both phones support each other’s LTE Bands. “Models A1688 and A1687 also support LTE networks listed for models A1633 and A1634.” and “Models A1633 and A1634 also support LTE networks listed for Models A1688 and A1687.” So it appears that they are the same regardless of what the specs page says.

    • kpom1 - 7 years ago

      They run on each other’s networks. However, the A1687/A1688 lack Band 30 support. Only AT&T uses it, and only as a supplemental band to increase capacity in urban areas. So you might get faster LTE with the A1633/A1634 but both models should give you access to the networks in the same areas.

  7. iSRS - 7 years ago

    They fact that LTE band 30 is AT&T only means they are both fine for world phones. The Verizon versions will work everywhere, too, just not that one band on AT&T

  8. I think Apple should be careful with releasing different iPhones under the same name. The thing that makes Apple so powerful is that you know you have the real deal for a while. First the Samsung-processor thing that fucks up your battery, and now this. Hmm.

    • spiralynth - 7 years ago

      Terrifyingly powerful.

    • kpom1 - 7 years ago

      You mean like Samsung, which produces some Galaxy S5 using its own chips and others running a Qualcomm chip that has completely different performance? They sold some S3 with a quad core processor and others with a dual core.

      The iPhone has the support for the most LTE bands of any major phone. Samsung makes a different S6 for Verizon that doesn’t support AT&T’s bands and vice versa. Neither support as many global bands. Apple makes 2 varieties of the iPhone 6s. The only difference is that one supports a very new band that AT&T is only starting to roll out in select areas (and no other carrier worldwide is using it) and the other does not. Both models work just as well as last year’s iPhone 6 on AT&T and have better global coverage.

      And Apple put out a statement that there real world differences between the TSMC and Samsung chips is minimal. AnandTech gave a detailed explanation of why that makes sense.

    • Brenda Patrick - 7 years ago

      How does the Samsung-processor fuck up the battery?

  9. kpom1 - 7 years ago

    Old news. My unlocked “AT&T” iPhone works with an active Verizon SIM, even on CDMA. I tried it on 9/25. Of course, try getting Verizon to open a new account with an “AT&T” iPhone and they’ll tell you it won’t work. But they should do so with the identical “SIM-Free” model.

  10. TranceMist - 7 years ago

    CDMA/EVDO is irrelevant outside the US, so it does not qualify as a worldphone feature.

    LTE band 30 is a relevant except for AT&T.

    So the differences are basically meaningless with regard to a worldphone.

    • Jeremy Horwitz - 7 years ago

      Depends on where you’re coming from. If you’re buying an iPhone outside of the USA (say, in the U.K.) and hope to be able to use it on Verizon in the USA, CDMA support would not be irrelevant to you. The U.K. iPhone promises to work on GSM only.

  11. Isaac Huben - 7 years ago

    The sim-free unlocked version should work with not problems in China, is that correct? According to some Chinese blogs, the phone will work with China mobile and China unicom, but will not work with the 3g and 2g networks of China telecom.

  12. Matthew Fox - 7 years ago

    bah!!!! i posted about this on mac rumors on September the 28th. i just don’t have my own website
    it was post # 21982428 in phone-6s-lte-30-band-and-cdma-version-megathread

    complete with the same urls.

    id post the url but its banned.

  13. Matthew Fox - 7 years ago

    i also posted on howard forums on september the 28th at 1871466-New-iPhone-6s-models-and-Verizon-whitelist with the same url. thanks for ripping me off and not crediting me

    • 89p13 - 7 years ago

      Ego problems much, Amigo?

    • Jeremy Horwitz - 7 years ago

      This should probably go without saying, but we never read either of your posts and don’t spend our time hanging out in those forums. On occasions where discussion forum posts have led to articles, we link to and attribute them. If we had seen your posts, we wouldn’t have waited until now to write something.

  14. Pete Anderson - 7 years ago

    I have a pretty basic question – if I buy a SIM free A1633, could I switch out the SIM from my Sprint 5S and it would work on Sprint (until I decide to change carriers), without having to contact Sprint, obtain a different SIM, pay for activation, etc?

    • I don’t /think/ so. Sprint is the oddball. Begs the question though, why the heck are you with Sprint??

    • Jeremy Horwitz - 7 years ago

      The phone hardware should certainly work on Sprint, but if Sprint maintains a registry of all phones, they may require activation.

  15. Awesome. I have always bought the Verizon model and brought it to AT&T. Used to be the cheapest way to buy an iPhone, and was the most compatible phone. I’m glad you did this research for me. I’m just waiting for iOS 9 on the 6s+ to jailbroken and then I’ll buy it.

  16. Joe Belkin - 7 years ago

    the charts you listed are confusing – can you mark the one this is OUTDATED? AND list the bands of the major countries?

  17. farookb4u - 7 years ago

    I got iPhone 6s A1633 sim free version and I confirm that CDMA Not working with India Reliance CDMA.

  18. John Tuong - 7 years ago

    Hey everyone – I have a question. So are both the AT&T A1633 version (Sim-Free and not Sim Free) compatible with Verizon? As said earlier in the article, the Apple website lists them as both GSM and CDMA EV-DO Rev. A – so in turn, does that mean that both AT&T A1633 models will work with Verizon?

    Story: My aunt has an iPhone 6S that she just gifted (she upgraded to the iPhone 6S Plus) and she gave me the not Sim Free version of the AT&T phone. Will this phone work on Verizon’s network? I just want confirmation before she sends the phone to me and for me to find it that it will not work on Verizon’s network.

    Thank you!