Apple tells iOS developers how to prepare apps for the iPhone Duo

Ahead of the foldable iPhone Duo launch, Apple published guidance for iOS developers: avoid fixed screen dimensions and UIScreen.main.bounds, rely on size classes and standard layout containers, and account for new reserved regions around the fold and cameras. Full support requires Xcode 27.1.

• Apple requires apps to handle the outer, inner and partially folded displays of the iPhone Duo
• Developers should use size classes and SwiftUI containers instead of UIScreen.main.bounds
• Navigation and toolbars may appear vertically on the side of the display
• Xcode 27.1 is needed to handle fold and camera reserved regions