iPhone Duo apps can now be submitted to the App Store, and Duo screenshots become mandatory in April 2027iPhone Duo apps can now be submitted to the App Store, and Duo screenshots become mandatory in April 2027

Apple began accepting App Store submissions of apps built for iPhone Duo on 5 October, 18 days before the foldable iPhone goes on sale.

Apple's developer news post confirms iPhone Duo will be available from 23 October. Apps are prepared by building or recompiling with Xcode 27.1, which adds development support for the device, and Apple points developers to Device Hub to see how an app behaves in each pose and orientation. Apple is also running iPhone Duo workshops for developers.

Existing apps will run on iPhone Duo without changes. MacRumors notes that only apps built with the iOS 27.1 SDK or later can resize to fill the inner display, and that apps which are not will appear with black borders.

When do iPhone Duo screenshots become required?

From April 2027. Apple says any app or game submitted from then on must include iPhone Duo screenshots. It has not given a day. Apple's screenshot specifications list two sets of sizes for the device:

• Outer display: 1398 x 2034 pixels portrait, or 2034 x 1398 landscape.
• Inner display: 2007 x 2853 pixels portrait, or 2853 x 2007 landscape.

App Store Connect also gains a preview tool that shows how screenshots, product page headers and other metadata appear on iPhone Duo, part of a wider change to App Store assets announced the same day.

Apple Configurator 2.21

Apple also released Apple Configurator 2.21 for the Mac on 5 October, MacRumors reports, with improved reliability when signing in with an Apple Account and unspecified bug fixes. Configurator is the tool IT departments use to set up iPhones and iPads with apps and profiles, and it is how many companies will prepare the first iPhone Duo units they hand out.

Our take

The two dates that matter are 23 October and April 2027, and they ask for different things. The first is about the app: anyone with users likely to buy an iPhone Duo should ship a 27.1 build before launch, because black borders on a 1,999 dollar folding screen are the first thing those users will notice and screenshot. The second is about the store page, and it applies to every app, including ones that never thought about folding phones. From April, a Duo screenshot is a submission requirement, not an option.

We noted a month ago that iPhone Duo ships on iOS 27.1 and its SDK was not out yet, and then that Xcode 27.1 beta added the Duo SDK and simulator 35 days before launch. Opening submissions 18 days out completes that sequence and is tight, given that App Review queues lengthen before a hardware launch. Apple's guidance remains that apps should not build their layout on the hinge, as in its advice on the iPhone Duo hinge angle.

APPDOOK's practical order for a small team: rebuild with Xcode 27.1 now and check the inner display in Device Hub, submit before the launch week, and leave the new screenshots until the app has been seen on real hardware. April 2027 is far enough away to take screenshots from a real iPhone Duo rather than a simulator, and they will be better for it.