How do I know if a iPhone 4s is Unlocked?
I'm buying a unlocked iPhone 4s from craigslist tomorrow. I just need to know how I can verify if it is unlocked. I have an old AT&T sim card I used to use for my iPhone 4. Not sure if that would work.
I just want to make sure it isn't sprint, or verizon with a bad ESN or something. I just want to make sure I can use the phone.
iMac, iOS 5.1