Apple has posted two new entries to their developer news page, the first warning developers they need to stop tracking people via UDID, and the second warning them they have to start supporting the double density Retina display, and 16×9 iPhone 5 and iPod touch 5 dip-lays, by May 1.
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 the UIDevice 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 the iOS Human Interface Guidelines.
Since features like 16×9 support require iOS 6, that also means iOS devices that don’t support iOS 6 likely won’t be compatible with new and updated apps. That includes the original iPad and iPhone and iPhone 3G. While Apple has provided excellent support for older devices over the years, especially compared to some of their competition, that’s certain to rankle customers still on those older devices.