What changes in your app on the iPhone Duo
The iPhone Duo came out on October 23, 2026. It has a narrow outer screen and a nearly square inner one, and your app resizes mid-session when you open or close it.
Published ·
Apple simulator · Demo data
It depends on how you built it
With the iOS 26 SDK or earlier, your app runs but doesn’t adapt. Opened, it sits in the center with empty space around it.
With iOS 27 it fills most of the inner screen and stays clear of the status bar on the right edge.
With iOS 27.1 or later it runs edge to edge on both screens, and system toolbars and tab bars turn vertical. Apple asks you to check that your content fits them before publishing.
What tends to break
Anything measured once at launch ends up wrong when the screen changes size.
Layout decisions based on whether the device is an iPhone or an iPad stop working, because an iPhone no longer has just one shape.
Full-screen images can lose important content on a wider screen, and anything tight against the right edge can end up under the camera.
On the App Store
If you upload iPhone Duo screenshots to App Store Connect, your listing shows a badge saying the app is optimized for it.
How to test it
Apple recommends the iPhone Duo simulator in Xcode 27.1. That’s what we use: we don’t have a physical Duo.