IOS 4.2 has been officially released. Like the IOS 4.1 and IOS 4.0.2, the new IOS 4.2 when you can not jailbreak. In addition, upgrading to a new baseband, making it impossible to unlock it with the current version of Ultrasn0w. So if you have a jailbroken and unlocked iDevice, it is best to stay away this new firmware until