AT&T has just announced that it will begin unlocking off-contract iPhones once the initial 2-year contracts customers’ sign up for expire. The new practice will allow currently-locked Apple devices to use micro-SIM cards from different carriers on networks compatible with the iPhone. The change will go into effect on Sunday, April 8.

AT&T relayed the following statement to MacRumors:

Beginning Sunday, April 8, we will offer qualifying customers the ability to unlock their AT&T iPhones. The only requirements are that a customer’s account must be in good standing, their device cannot be associated with a current and active term commitment on an AT&T customer account, and they need to have fulfilled their contract term, upgraded under one of our upgrade policies or paid an early termination fee.

In February, it was reported that AT&T agreed to unlock an off-contract iPhone 3GS, after a customer sent a letter to Apple CEO Tim Cook. AT&T called this unlocking a “special one-time exception,” but now appears to have changed their stance on the matter. The complaint sent to Cook was from a customer who had moved to Canada, and still wanted to use his iPhone.

For some time now, users have been unlocking various Apple devices minutes after they would first hit the market. It’s about time AT&T relented on something.