Apple previously told developers that iOS and iPadOS 13 SDKs would be required as of April, but did not give a specific date.
iOS 13 is now running on 77% of all iOS devices introduced in the last four years, worldwide. Deliver great user experiences by seamlessly integrating with Dark Mode, Sign in with Apple, and the latest advances in ARKit 3, Core ML 3, and Siri. Starting April 30, 2020, all iPhone apps submitted to the App Store must be built with the iOS 13 SDK or later.
Take advantage of Xcode features such as storyboards (including launch storyboards), Auto Layout, and SwiftUI, to ensure your app's interface elements and layouts automatically fit the display of all iPhone models, regardless of size or aspect ratio. Starting April 30, 2020, all apps submitted to the App Store must use an Xcode storyboard to provide the app's launch screen and all iPhone apps must support all iPhone screens.
Apple also says that as of April 30, all apps must use an Xcode storyboard to provide the launch screen. All iPhone apps must support all iPhone screens, and all iPad apps must support all iPad screens.