The framework before the device
Apple did not announce the foldable iPhone at the WWDC 2026 keynote — hardware is expected at the September iPhone event — but it shipped the foundational SDK pieces in iOS 27 to give developers a head start. As documented by Lushbinary in its post-keynote technical breakdown, SwiftUI and UIKit receive new adaptive layout APIs: hinge-state detection and multi-configuration display handling.
Apple's stated expectation is that apps on the foldable iPhone should reflow fluidly rather than letterbox, which requires structural work for many apps, especially those with rigid layouts or interfaces optimised for fixed aspect ratios. The mechanism mirrors what was already introduced on iPad with Stage Manager: when the device opens or closes, the app must re-layout in real time.
A roadmap signal
The move implicitly confirms a September 2026 timeline for the foldable iPhone. Apple would not publish hardware-specific frameworks without a fixed release calendar. For developers, the practical message is clear: those who adopt the new APIs now will have day-one ready apps; those who wait will be playing catch-up.