Techincally, as of the writing of this post, all iPhone 4S's should be under contract, which is against the unlocking policy.
For example, if I buy a used 4S, and tell AT&T i bought it used, will they unlock it? Or is there a risk, and I should buy a factory unlocked one instead?
For example, if I buy a used 4S, and tell AT&T i bought it used, will they unlock it? Or is there a risk, and I should buy a factory unlocked one instead?