If you don’t know what this refers to, wikipedia can explain it. Anyone running Apple’s iOS has a software-readable serial number – a “Unique Device Identifier,” or UDID. Eric Smith, a Bucknell ...

The UDIDs are used to create an Apple-certified provisioning file that is dragged with the app into iTunes. The UDID is not visible on the phone. It has to be revealed in iTunes, and it cannot be ...