[DigitalToday reporter Jinju Hong] Apple will require apps and games listed or updated on the App Store from April 2027 to submit screenshots for the iPhone Duo. Submissions are currently optional, but Japan's ITmedia reported on Oct. 6 that they will become a mandatory requirement for review applications filed after that point.

The rule will not be limited to newly released apps. Updates to existing apps will have to follow the same standard. The iPhone Duo, the first foldable iPhone, is effectively changing app distribution standards themselves.

The iPhone Duo is Apple's foldable iPhone unveiled in September. It is set to be released on Oct. 23. It has a 5.4-inch external display used when the device is folded and a 7.6-inch internal display used when it is unfolded. As a result, app product pages now require promotional images that reflect both screen environments.

The images Apple requires are screenshots that show app screens and features on the App Store product page. Under specifications Apple has released, images for the iPhone Duo support 1,398 by 2,034 pixels for the external display and 2,007 by 2,853 pixels for the internal display. Sizes tailored for a landscape-oriented screen will also be accepted.

Work to prepare developers is also under way. Apple instructed developers to rebuild existing apps with Xcode 27.1, which supports iPhone Duo development. Using the testing tool Device Hub included in Xcode, a virtual iPhone Duo can be run on a Mac. The tool is designed to reproduce opening and closing of the device and screen rotation, and to allow checks of app display and operation when screen size or orientation changes.

Apple also added a feature to check how content will appear before app review. It added a new preview function to App Store Connect, its app registration management tool. Developers can check in advance how screenshots and the header image at the top of the product page will look on the iPhone Duo product page.

Apple also released design guidelines and templates for image production on its official website. The move shows a shift from a simple recommendation to prepare app promotional assets tailored to foldable screen ratios to a formal review standard.

This measure is seen as accelerating efforts to reorganise the app ecosystem after the launch of the foldable iPhone. Developers will have to prepare visual materials that take into account the external screen and internal screen separately, and existing apps will have to go through the same process during updates. As a result, support for the iPhone Duo is expected to become a basic requirement not only for app optimisation but also for App Store exposure and passing review.