Unlocking Initially most wireless carriers in the US did not allow iPhone owners to unlock it for use with other carriers. However AT&T allowed iPhone owners who have satisfied contract requirements to unlock their iPhone Instructions to unlock the device are available from Apple but it is ultimately the sole discretion of the carrier to authorize the device to be unlocked This allows the use of a carrier-sourced iPhone on other networks. Modern versions of iOS and the iPhone fully support LTE across multiple carriers despite where the phone was originally purchased from There are programs to remove SIM lock restrictions, but are not supported by Apple and most often not a permanent unlock – a soft-unlock. [156]