Every iPhone has a digital "policy" stored on Apple's servers. When you insert a SIM card, the phone asks Apple: "May I work with this carrier?" If the policy says "Locked to T-Mobile USA," the phone rejects other SIMs.
Iran has a unique telecommunications landscape. The two major carriers—Hamrahe Aval (MCI) and Irancell—often sell iPhones at subsidized rates in exchange for a 12-to-24-month lock period. Additionally, many Iranians purchase second-hand iPhones from the UAE or Turkey, which may be locked to foreign carriers like Etisalat or Vodafone. iphoneunlocker.ir
Because the unlock is registered with Apple’s servers, you can update, restore, or wipe your phone—the unlocked status remains forever. Every iPhone has a digital "policy" stored on