Summary of notable changes in iOS app development (2026/09/18)
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On September 15, 2026 (Japan time), iOS 27 / iPadOS 27 and Xcode 27.0 were officially released. On the same day, iOS 26.7 / iPadOS 26.7, a security update for the iOS 26 line, was also published. Additionally, this week was packed with updates, including the distribution of iOS 27.2 / Xcode 27.2 beta, an issue with version display in Software Update, and support for Markdown retrieval in Apple Developer documentation.
The previous article compared the RC release notes from Beta 4 and summarized developer-facing changes accompanying the announcement of iPhone Duo. This article organizes various information accompanying the official release, changes newly confirmed from the release notes that warrant consideration for app maintenance, and highlights from the iOS 27.2 beta. No verification on actual devices has been performed; this is based on the content of release notes and official documentation.
Apple
iOS 27 / iPadOS 27 Official Release
The previous article summarized the differences from Beta 4 to RC. With the official release, these changes have been finalized.
Xcode 27.0 Official Release
Xcode 27 Release Candidate (27A266a) was officially released as Xcode 27.0 (27A266a) with the same build number. Since it is the same build, there are no functional changes from the RC.
Coding Intelligence (Google Antigravity, agent plugins, xcrun mcp-server preview) and Previews improvements mentioned in the previous article are included in the official release as-is. Swift 6.4 bundled with it includes a wide range of improvements: simplification of available attributes with anyAppleOS, defer support in asynchronous code, for-in loop extensions to non-copyable types such as Span and InlineArray, up to 4x faster URL parsing in Foundation, and interoperability between Swift Testing and XCTest.
App Store Connect Update
Apps built with the iOS 27 SDK in Xcode 27 can now be uploaded to the App Store and TestFlight (both internal and external testing). Supported SDKs are iOS 27.0, iPadOS 27.0, macOS 27.0, tvOS 27.0, visionOS 27.0, and watchOS 27.0.
Xcode 27 Now Available on Xcode Cloud
The previous article stated that "Xcode 27 RC has not yet been rolled out to Xcode Cloud," but it subsequently became available (as of September 13, 2026, 2:15).
iOS 26.7 Security Update
iOS 26.7 / iPadOS 26.7 was released on September 15, 2026 (Japan time). No release notes were published; only security notes are provided.
The security notes include fixes across a wide range of components such as Kernel, ImageIO, WebKit, Bluetooth, AVEVideoEncoder, CoreMedia, and CoreML. There is no mention of active exploitation, but fixes related to kernel privilege escalation and remote code execution are included, so those remaining on iOS 26 should consider applying the update promptly. The author has multiple devices for development and needs to maintain iOS 26, so the author has updated to 26.7.[1]
Issue with Version Display in Software Update
As of 5:00 AM Japan time on September 15, 2026, multiple reports appeared on X (formerly Twitter) of iOS 26.7 being installed despite selecting iOS 27 in Software Update. Similar reports came from users around the world, not just Japan.
At that point, there was no official announcement from Apple.[2]
iOS 27.2 / Xcode 27.2 Beta Release
iOS 27.2 beta was released along with Xcode 27.2 beta. iOS 27.1 is a dedicated track for iPhone Duo, and existing iPhones will be updated directly from iOS 27.0 to 27.2. The Xcode 27.2 release notes also state that "iOS SDK and simulator support for iPhone Duo will be provided in a future Xcode 27.1 release." It can be assumed they will merge in a future version; there is a precedent from 2010 when the first iPad was released and iPhone OS 3.2 ran as an iPad-dedicated track before being unified with iOS 4.2.1.
In iOS 27.2, AppTrackingTransparency (ATT) now supports an expanded prompt and annual re-prompting for EU users. An alternative expanded prompt is mandatory for users in France, Germany, Italy, Poland, and Romania. If you are distributing apps to the EU, action will be required.
In StoreKit Testing in Xcode, an issue mentioned in the previous article as a Known Issue — where changing the storefront or locale in SKTestSession did not propagate to Storefront.updates — has been fixed.
Xcode 27.2 adds new support for JSON-format project files (.xcproj). Compared to the traditional .xcodeproj (plist format), merge conflicts are much less likely to occur in practice, and it is said to make editing by coding agents easier as well. It can be enabled from the File Inspector, and can also be opened in Xcode 27 versions prior to Xcode 27.2.
Changes to Consider for App Maintenance
Scene-based lifecycle requirements, Liquid Glass requirements, removal of ld64, Apple silicon exclusivity, TabView selection behavior changes, and deprecation of On Demand Resources are covered in detail in the following past articles.
Also, the previous article covered breaking changes in MetricKit, changes to iPad resize behavior, the mandatory migration of UIScreen.main, deprecation of PHAssetResource.originalFilename, precision changes to volumeAvailableCapacityKey, deprecation of devicectl JSON version 5, and deprecation of canOpenURL(_:).
The following are changes newly confirmed in the official release notes.
- Apps built with the iOS 27.0 SDK or later must have a launch screen configured in
Info.plist(one ofUILaunchStoryboardName,UILaunchStoryboards,UILaunchScreen, orUILaunchScreens). Apps without this setting will be rejected from the App Store. - SwiftUI's
@Statehas switched to a new implementation via macros. There are source-level incompatibilities, including code that assigns a value within an initializer to a@Statewith an initial value at declaration becoming a compile error, and the synthesized initializer being disabled when all stored properties are private. This can affect all apps built with Xcode 27, regardless of deployment target. Note that the new behavior that avoids re-evaluation is itself back-deployed to iOS 17 and later. - Existing entities adopting the
@AppEntity(schema: .photos.asset)schema may fail to compile with the 27.0 SDK. Since new properties have been added to the schema, this can be worked around by adopting the additional properties and adding availability checks. - A system text selection UI and additional gestures have been added to
Textviews with.textSelection(.enabled)applied. If this conflicts with custom gestures, consider using.highPriorityGesture(). PreviewProviderhas been deprecated. Migration to the#Previewmacro is recommended.
Apple Developer
Documentation Now Available in Markdown Format
It is now possible to retrieve documentation pages on the Apple Developer site in Markdown format by appending .md to the end of the URL. No official announcement was found, but it worked on our end.
For example, accessing https://developer.apple.com/documentation/uikit/uitableviewcontroller.md, which adds .md to the documentation URL for UITableViewController, returns the same content in Markdown format. The same applies to release notes such as iOS & iPadOS 27 Release Notes.
This eliminates the need to parse HTML when having an LLM reference Apple documentation, making integration with MCP servers and RAG easier. This .md format was also utilized when referencing release notes for this article.
Summary
The tricky part of this release is that changes like the mandatory launch screen requirement and the macro-based @State can lead to rejection or compile errors if you upgrade builds without noticing them. When migrating to building with the iOS 27.0 SDK, be sure to check the items listed in this article and past articles beforehand. iOS 27.2 beta has also introduced noteworthy changes for future updates, such as ATT EU compliance and JSON-format project files (.xcproj).
The author publishes several personal development apps and plans to continue building with Xcode 27.0 to identify any issues that arise.
Job Listings: Classmethod is Hiring iOS Engineers
The Starbucks Digital Technology division is looking for engineers capable of iOS app development. We look forward to applications from those who would like to work with us while sharing information about new Xcode and iOS features in the misc-ios channel!
We are also hiring iOS/Android engineers in other areas. Let's talk about mobile app development together!
As a side note, several CVEs in the security notes' acknowledgements credit "Calif.io in collaboration with Claude and Anthropic Research." It is an interesting example of AI being utilized in security vulnerability discovery. ↩︎
This issue may have been resolved before this article was published, so please check the latest status on your own. ↩︎