As of February 2015, cell phone carriers offer free unlocking of devices, including the iPhone 4s for customers who meet certain conditions. This eliminates the need for finding a backdoor to unlock phones.
Carriers require the device be off-contract and the customer be in good standing before they allow unlocking. For phones the consumer purchases on a payment plan, the customer must fulfill the contract before the carrier unlocks the phone. The customer initiates the unlocking process by contacting the carrier. In some cases, the carrier provides unlock codes or other instructions to unlock the phone at home; however, other carriers require customers bring phones into the store for unlocking.
All carriers offer device unlocking under the new agreement. The agreement applies to both prepaid and postpaid cellular devices. With prepaid devices, carriers require the user to own the device for a year before providing unlocking services.
Some carriers automatically unlock their cellular devices when they become eligible, but others simply notify the customer when his phone becomes eligible. According to the agreement, carriers do not charge customers or former customers to unlock the devices, although they have the option of charging individuals who have never been customers for the service.