Apple has issued a strict mandate to developers that all apps must be adapted to foldable screens by April next year.

Recently, Apple has announced new app submission rules for its first foldable iPhone Duo to global app developers, requiring developers to adapt their apps to iPhone Duo, otherwise new apps and updates will not pass App Store review starting from April next year.

On October 7, the entry "Mandatory Adaptation for iPhone Duo" became a trending search on Weibo.

Earlier, on October 5, Apple released an announcement on its developer official website, clarifying that all new apps and version updates submitted on App Store Connect from April 2027 must come with app screenshot materials adapted for the iPhone Duo model. This policy marks that Apple has officially established the access standards for listing apps on the foldable iPhone.

Apple stated in the document that April 2027 is the mandatory enforcement node, and the current period is a transition phase. Old apps that have already been listed will not be affected and can still be used normally; but once an update is submitted, the adapted screenshots must be supplemented, otherwise the submission will be rejected.

On September 10, Apple launched its first foldable phone iPhone Duo at the autumn new product launch event. The product will open pre-orders at 20:00 on October 16 and be officially released to the public on October 23.

The iPhone Duo features an inner and outer dual-screen form, with a 5.4-inch outer screen when closed and a 7.6-inch large screen when unfolded. Apps need to adapt to the display logic under different opening and closing postures.

Apple has opened a full set of supporting development resources to developers in the announcement. Developers can recompile existing apps with Xcode 27.1. The new version of the development tool has a built-in iPhone Duo simulator, allowing developers to preview the running effect of apps on the foldable device at different opening and closing angles and in portrait and landscape orientations in Device Hub, to troubleshoot adaptation issues such as disordered interface layout and truncated content in advance.

Apple has also launched the app material specification page, which provides production standards and template files for screenshot sizes, layouts and preview videos, lowering the threshold for developers to produce materials.

The App Store Connect release notes have also updated the details of the submission rules. The new rules apply to both apps and games, with no category exemptions. The core mandatory requirement of the policy is the submission of screenshot materials: developers need to upload screenshots of the app running on both the outer screen and the inner screen respectively, for display on the App Store product page.

Market analysis believes that this rule from Apple does not equal to mandatory requirements for all apps to complete in-depth foldable interaction optimizations such as split-screen and windowing. The bottom line of the policy is that apps can run normally on the iPhone Duo hardware.

The iPhone Duo comes pre-installed with the iOS 27.1 system. Built on the underlying iOS 27, this system has specially added system capabilities adapted to foldable hardware to handle basic logics such as screen opening and closing switching and layout adaptation.

In the initial stage of the launch of its first foldable phone, Apple does not force existing apps to complete in-depth transformation immediately, and reserves a buffer period of more than half a year to push developers to gradually evaluate the adaptation requirements for foldable screens.

A research report released by Apple on October 8 shows that in 2025, the App Store ecosystem in China generated approximately 4 trillion yuan in turnover and sales, an increase of 107% compared to 2020. At the same time, among the revenue Chinese developers obtained from the App Store, the contribution from overseas markets has risen from 32% five years ago to 52%.

In comparison, the construction of the Android foldable screen ecosystem has undergone several years of gradual iteration. Google did not set hard listing thresholds for app developers in the early stage, to avoid imposing excessive development burdens on small and medium-sized developers at one time. The Android system relies on the compatibility mode as a fallback, and non-adapted apps will run with letterbox black borders to ensure basic availability, but they are prone to experience defects such as interface stretching and disordered layout, which is the core reason why early Android foldable products were criticized for their ecosystem shortcomings.

Subsequent Android 12L, Android 16 and Android 17 have gradually enhanced the large-screen adaptation capability, and guided apps to support scalable windows at the underlying level through API rules, which is a gradual constraint at the system level rather than a mandatory review in the app submission process.

Xiaomi, OPPO, vivo and Honor in China have jointly established the Gold Label Alliance, and launched large-screen adaptation specifications in 2023, setting three levels of standards: basic availability, perfect adaptation and in-depth gold label. Only crashes and core function failures are regarded as red lines for review, while in-depth optimizations such as adaptive layout, split-column and hover interaction are recommended items. Apps that complete high-quality adaptation can get the store's gold label tag and traffic tilt, but the gold label certification is not a necessary condition for listing.

The purpose of Apple launching this new rule is to avoid the ecosystem shortcoming of "hardware first, software lagging behind" that plagued the Android foldable screen ecosystem in the early years in advance. Relying on the review right of the App Store as the only distribution channel, Apple uses the material submission rule to push developers to evaluate the display performance of apps on the inner and outer screens in advance, laying a software foundation before the iPhone Duo goes on sale. For Apple, the unified display standards also help shape the complete product experience of the foldable iPhone, taking the software ecosystem as the core competitiveness of this new product and building differentiated advantages in the mature foldable track.

According to the forecast of market research institution Counterpoint Research, global foldable phone shipments will increase by 21% year-on-year in 2026; the upper limit of shipments of Apple's first foldable model iPhone Duo this year can reach 6 million units, which is expected to capture 25% of the global foldable phone market share, ranking second in the world, second only to Samsung's 38%, while Huawei is expected to rank third with 22% share.

In the domestic market, Huawei previously took more than 70% of the share with its product matrix. After the Apple iPhone Duo is launched, it will divert a large number of high-end Apple users, and jointly divide the domestic foldable phone market above 10,000 yuan with Huawei and Xiaomi.

This article is from the WeChat Official Account "Jiemian News", author: Shen Xiaoge, published with authorization from 36Kr.