Make your app fit iPhone Duo
Everything you need to get an existing iOS app ready for iPhone Duo: what to change in your code, how to test every pose, and how to ship an update that fills the inner display.
Step 1
Start here
Step 2
Layout
- Size from the window, not the screenFind and replace the five screen assumptions that stretch, clip or misplace content on iPhone Duo.
- Size classes, safe areas and standard containersLet size classes, safe areas and system containers do the adapting, so one layout serves every pose.
- Vertical toolbars and tab barsPrepare your bars before you build with the iOS 27.1 SDK: containers, symbols, axis behavior, overflow and priority.
Step 3
Platform features
- Hinge, poses and adaptive layoutsReserved regions, ArrangementView and onHingeChange: what each is for, and when not to use them.
- Split View, multiple windows and keeping stateYour app can now share the screen and open more than one window. What to handle, and what you get for free.
- Camera apps and the outer displayTwo front cameras, a camera that may face either way, and the one way to put UI on the outer display.
- Games, video and motion on iPhone DuoKeep games playable in every pose, avoid black bars, and get motion data that matches the screen in use.
- Websites and web views on iPhone DuoResponsive design is the whole strategy. The foldable web APIs exist, but only behind a Safari flag.
Step 4