According to Apple’s updated App Store submission requirements, iOS developers will soon need to update their existing apps as well as any new iPhone or iPad apps to be fully compatible with iOS 12.1.
Starting March 27, 2019, Apple says that all new apps and app updates for iPhone or iPad, including universal apps, must be built with the iOS 12.1 SDK or later and support iPhone XS Max or the 12.9-inch iPad Pro (3rd generation). At the same time, screenshots for these devices will also be required.
“iOS 12 is now running on more than 80% of devices worldwide. Make sure your app delivers a great user experience by seamlessly integrating with the latest advances in iOS.”
Similarly, all new apps and app updates for Apple Watch will need to be built with the watchOS 5.1 SDK or later and support Apple Watch Series 4.
Apple’s new submission guidelines also note that iOS 12 and tvOS 12 require apps to use memory far more efficiently than before. Developers who are having difficulty reducing their app?s memory requirements can contact Apple and request an entitlement for their app to use iOS 11-style memory accounting.
More information is available at Apple’s developer website.