iPhone Duo App Store submission checklist

iPhone Duo submission checklist

Tick these off before you upload. They cover the build, the scene life cycle, layouts, screenshots, and the review rules that did not move.

Build or recompile with Xcode 27.1

Apple’s 5 Oct 2026 developer news says to build or recompile with Xcode 27.1, which adds development support for iPhone Duo. The iPhone Duo developer page points at the Xcode 27.1 release candidate for the SDKs you build, run, and test with.

Older Xcode builds do not use the full inner screen. Recompile so the inner display is the canvas your layout actually gets, then open Device Hub and check every pose and orientation.

You can submit those builds in App Store Connect now. iPhone Duo goes on sale 23 Oct running iOS 27.1.

Adopt UIScene before you rebuild

TN3187 is Apple’s note for moving to the UIScene life cycle. Apps built with the new SDK will not launch without it. That is a launch failure, not a layout warning.

If you ship a wrapped app — Capacitor, React Native, or Flutter — confirm the framework version you will rebuild with already supports the scene life cycle. Rebuilding on an older wrapper is how this shows up as a crash on first launch.

SwiftUI apps that use the App protocol already run on scenes. UIKit apps still need a scene configuration before you archive with the new SDK.

Layouts, cameras, and what to test

Size the interface to the container or the scene, not to the screen. Use size classes. Do not branch layout on device type or on orientation.

Test every state in the iPhone Duo simulator and in Device Hub: outer display, inner display fully open, folded, and rotated.

Camera apps have an extra case. The active camera can change when the phone is opened, closed, or rotated. Handle that switch. Do not assume the camera you started with is still the one in use.

In Review Notes, say which flows work on the outer display and which need the inner display, and write the path a reviewer follows to reach each one.

Screenshot sizes to upload

Apple’s screenshot specifications list iPhone Duo upload sizes. Outer display: 1398×2034 pixels, or 2034×1398 in landscape. Inner display: 2007×2853 pixels, or 2853×2007 in landscape.

Those Duo screenshots are optional today. From April 2027, every submission needs them.

The sizes App Store Connect still requires today did not change. For iPhone, provide at least one screenshot for iPhone with Dynamic Island (medium display). If the app supports iPad, also provide a 13-inch iPad screenshot.

From April 2027, every upload must also be built with the iOS 27 SDK. That SDK rule is separate from the Duo screenshot rule. Meeting one does not meet the other.

Preview the product page

App Store Connect’s preview tool shows your screenshots, product page headers, and other metadata on iPhone Duo before you submit. Use it on the build you are about to send.

New product page header images and search result images are optional. They do not replace the Duo screenshots.

What usually does not change

Privacy nutrition labels still have to match the binary and its SDKs. A foldable display does not create a new data type.

If the app creates accounts, in-app account deletion is still required. Duo does not move that to a website-only flow.

In-app purchase and Small Business Program terms are unchanged by this hardware. EU storefront rates are a separate map.

Guideline 4.2 (minimum functionality) still applies. A cover widget or a thin inner webview is not a new exception.

Guideline 2.1 (app completeness) still applies. Screenshots, previews, and Review Notes have to match the build a reviewer installs.