Dec 21, 2010 · A UDID, or “Unique Device Identifier,” is simply a specific serial number for your iDevice. There are multiple advantages to having this device-specific serial, but it mainly serves as a way to document the existence of your device and to track it. Think of your iPhone’s UDID as its social security number. UDID, the abbreviated form of Unique Device Identifier, is a 40-digit serial number for each iOS device to Part 1. What You Need to Know about UDID of iOS Device. 1. Why UDID id Needed?
What is an UDID file? The UDID file extension indicates to your device which app can open the file. However, different programs may use the UDID file type for different types of data.