Apple confirmed to Engadget on Tuesday that the T-Mobile version of the iPhone 5 carries the same A1428 model number as the AT&T iteration, but has AWS enabled thanks to a factory tweak. The change can't be duplicated by a firmware update, meaning current AT&T iPhone 5 owners must buy the newest version if they want AWS functionality.
As a consolation, the new A1428 model will be factory unlocked when it ships on April 12, the same day as T-Mobile's launch date for the device. Apple will reportedly be selling the unit at full MSRP prices in a "SIM-in unlocked fashion." While the handset has been customized for T-Mobile's AWS bands in the U.S., AT&T customers will be able to take advantage of the slightly revamped model on their 4G LTE network.
The publication goes on to say that Apple is phasing out the older A1428 model in favor of the T-Mobile-compatible version, suggesting that AT&T iPhone 5 units sold after April 12 will support AWS.
T-Mobile announced on Tuesday that it will be offering the iPhone 5 as part of the company's unsubsidized payment plan, which allows users to pay a low $99 up front fee for a 16GB version of the smartphone, with the remainder of the unit's cost spread out across 20 additional monthly payments of $20.