iPhone dev team has just tweeted screenshot displaying a text message from AT&T informing users to update to latest firmware. This is first time we have seen a software update message from carrier to iPhone users. This means that AT&T wants to push users for updating iPhone to latest firmware their by losing their jailbreak & unlocks.
If you have iPhone with older firmware & jailbroken and if you receive such message please ignore it as Dev team says its trap, especially ultrasn0w unlockers don’t fall into this trap.
AT&T Text message to update iPhone