Device Identifiers
The client is responsible for generating the device ID. It must ensure that the device ID is unique to the device and does not change. Examples are:
apple:udid:bc933a993bd5e31a2f6049154274ec0e2d76fcfa (UDID, iOS 5 and earlier)
apple:vendorId:1DD28095-D747-4B04-8AA7-3439FFF47FBE (vendor identifier, iOS 6 and later)
samsung:serial:ecda4c0aea9865be (Android)
When upgrading to another device ID generation schema (such as a transition from iOS 5 to iOS 6), you must look up the old device ID first (using GET /devices/<identifier>) to avoid creating a duplicate device.
