Apple has warned developers for nearly a year that apps should not use UDIDs, and that they will be rejected in the future. A deadline has finally come on UDID apps, as Apple just announced they will reject any apps that use UDIDs starting on May 1st.
Another stipulation on Apple’s deadline, is that all apps must support the iPhone 5’s 4-inch display too. Here are the full notes on the deadline:
Using Identifiers in Your Apps
Starting May 1, the App Store will no longer accept new apps or app updates that access UDIDs. Please update your apps and servers to associate users with the Vendor or Advertising identifiers introduced in iOS 6. You can find more details in theUIDevice Class Reference.
Make Your Apps Look Great on the Retina Display and iPhone 5
Starting May 1, new apps and app updates submitted to the App Store must be built for iOS devices with Retina display and iPhone apps must also support the 4-inch display on iPhone 5. Learn about preparing your apps by reviewing theiOS Human Interface Guidelines.”
Source: Apple