AT&T has started allowing out-of-contract customers to unlock their iPhone and use it on another carrier.

Beginning Sunday, April 8, we will offer qualifying customers the ability to unlock their AT&T iPhones, read a statement issued by the carrier Friday. 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.

Until now, AT&T customers who completed the terms of their two-year contract with the carrier had an iPhone that could not be unlocked through official avenues. That meant even though they were free to leave for another carrier, they could not bring their iPhone with them, AppleInsider reported.

For users who travel overseas, an unlocked iPhone is ideal as they can use a cheaper SIM card from a local GSM wireless carrier, rather than paying for expensive service from AT&T, PCWorld reported.

The reports also added that Unlocked AT&T phones will work on T-Mobile's network, though data speeds will be slower than 3G. In addition, AT&T's unlocked phones won't work on Sprint or Verizon, due to their use of CDMA networks that don't rely on SIM cards.

iDownloadBlog has provided the process to use AT&T's online chat to unlock the out-of-contract iPhones. Below are the steps to follow:

Step 1: On your phone go to Settings > General > About > and locate your IMEI number.

Step 2: Visit AT&T's chat support page, (you will need to be logged in to do this). After logging in, click Chat Now next to Technical Support.

Step 3: Fill out the chat form, and type I want to unlock my iPhone 4″ in the How may we assist you today? field. Click Start Chat.

Step 4: Explain to the representative that you need to unlock your iPhone, and provide them with the IMEI number from. This will allow the representative to determine the eligibility of your iPhone unlock.

Step 5: If the device is eligible for an unlock, the representative will ask for your email address. They will provide you with further unlock details via your email address. It could take a week for the unlock request to completely go through.

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