Another question about UDID ...
UDID is a unique identifier for the phone, but the IMEI number is also a unique identifier. I understand that a device can have different MAC adress, but the IMEI is unique.
So my question is should I use IMEI as a fallback of the UDID. Although, if the UDID has been deprecated to avoid customer tracking, is it possible that Apple will reject application that use the IMEI number, or even disable the possibility to access the IMEI number ?