iPhone Duo support by framework
Apple ships adaptive APIs for SwiftUI and UIKit. Every cross-platform framework is, as of today, on its own — which is why the guides below separate what Apple has documented from what we have inferred.
SwiftUI
First-party supportSwiftUI has first-party iPhone Duo support. ArrangementView, ReservedRegion and the vertical toolbar APIs ship in the iOS 27.1 SDK.
Read the guide →UIKit
First-party supportUIKit has full first-party iPhone Duo support, with UIArrangementViewController, UIViewReservedRegion and vertical bar APIs in the iOS 27.1 SDK.
Read the guide →React Native
No vendor supportReact Native has shipped no iPhone Duo support. Core layout works, but the new adaptive APIs need a native module and several common patterns break.
Read the guide →Flutter
Partial / unconfirmedFlutter has mature foldable support on Android through MediaQuery.displayFeatures, but nothing equivalent has shipped for iPhone Duo on iOS.
Read the guide →Unity
No vendor supportUnity games face resolution changes mid-session on iPhone Duo, plus safe-area and pause-behaviour issues that a fixed-resolution game has never handled.
Read the guide →Capacitor & web views
No vendor supportWeb-based iOS apps adapt well to iPhone Duo if they use CSS environment variables correctly and treat the viewport as genuinely variable.
Read the guide →