I have an iPhone 4S on AT&T. It was jailbroken and I decided I wanted to update my phone to the latest OS. The phone updated perfectly (apparently) but when I go to activate my phone, I can. I'm asked for Language, Country, I connect, and when I push to activate, I get the following error message: "Your iPhone could not be activated because the activation server is temporarily unavailable. Try connecting your iPhone to iTunes to activate it, or try again in a couple of minutes." This problem has persisted over several days, and I've seen several others across several carriers encounter the same problem. I've tried to activate over wi-fi, my cellular network, and iTunes. I put the phone back in DFU mode and restored it again on iOS 6.1.3, but to no avail. I took it to the Apple store and their "technician" tried to activate it and couldn't. He even put in a different SIM card and it still wouldn't activate. He told me that the phone is out of warranty (I have had it over a year) and would need to pay $199 to replace it without affecting my contract. That's a load of bollocks if all I did was connect my phone to perform a standard update in the first place.