According the iOS 5 features page on Apple's web site, the 3GS is supported. When I push the "Check for Update" button in iTunes, it says "This version of the iPhone software (4.2.1) is the current version." I'm running iTunes 10.5.142 on Windows. I have also used this same setup to upgrade my iPhone 4.

Is there something else I need to do here? Could it be refusing because this phone does not have a carrier anymore and I use it only over WiFi?

  • I updated my iTunes first and then the update for the iPhone showed up. I updated my iPhone 3GS and beware it is a process... a scary one! I takes a while to finish the update... There are quite a bit of changes with it so be ready. The main change I noticed was the contacts.. it wouldn't let me edit or delete a contact. Let me know if you have the same problem!
    – user12966
    Commented Oct 29, 2011 at 20:03

3 Answers 3


Simple answer: You don't have a 3GS, but rather a 3G. The last iOS update for the 3G was 4.2.1. A 3GS ran all the way up to 4.3.5, which was the last public release of iOS 4. If you are running 4.2.1 and iTunes doesn't even see the 4.3.5 update, then, well, that's pretty telling that you don't actually have a 3GS but a 3G.

  • It self-identifies as a 3GS: i.imgur.com/7CTei.jpg Commented Oct 30, 2011 at 17:56
  • 2
    @MatthewSimoneau The name of the device can be changed to anything you like: cl.ly/0E082x2R1k1h3D0G0V37. It's a 3G. Look here on how to identify your model properly: ifixit.com/Info/ID-your-iPhone
    – user10355
    Commented Oct 30, 2011 at 21:39
  • Sure enough. A previous operator changed the name of this iPhone 3G to "iPhone 3GS". It's crazy that the only way to reliably determine the model number is to read a tiny code on the back of the phone and cross-reference that against a table. Anyway, thanks for your help. Commented Nov 4, 2011 at 1:02
  • @MatthewSimoneau Reliably yes. But there are other subtle hints, just as the 3G not having the ability to sport a wallpaper on anything but the lock screen (resulting in a black "void" under the icons. A lack of multitasking is another dead give away. In any case, Apple has never really branded their products with flashy badges (other than their corporate logos) or unit iterations. It is part of their design philosophy and adds to their products appeal, you it's hard too get to upset about it.
    – user10355
    Commented Nov 4, 2011 at 4:44

Could be a couple of things, most likely your iTunes version

  • verify that you are running the latest version of iTunes (version 10.5)

  • The latest version of iTunes requires Mac OS 10.5 or above

  • Thanks for the ideas. I'm running iTunes 10.5.142 on Windows. I have also used this same setup to upgrade my iPhone 4. Commented Oct 29, 2011 at 18:01

As above, The 3GS does support IOS 5, Update your itunes to the latest version should sort that out. Also try on a different computer, maybe your host files have corrupted.


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