Summary of Notable Changes in iOS App Development (2026/10/17): Xcode 27.1 Officially Released, App Review Guidelines Revised, and More
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With the iPhone Duo launching on October 23, there have been several Apple-related developments relevant to maintenance, including the official release of Xcode 27.1 and revisions to the App Review Guidelines. Here is a summary of the topics that caught my attention.
Apple
Xcode 27.1 Released
Xcode 27.1 was officially released on October 15, 2026. The build number is 27A9275, the same as the RC, and the SDKs are iOS 27.1, plus 27 for iPadOS, tvOS, watchOS, macOS, and visionOS. iOS 27.1 is the version for the iPhone Duo, so you can now submit iPhone Duo-compatible apps using the official release of Xcode.
Compared with the RC release notes, the only addition in the official release is one Known Issue, and all the Known Issues from the RC release notes remain. The added issue is as follows.
- In the iPhone Duo simulator, an app that uses
CameraCaptureAccessorycan use both displays at the same time without a camera capture session
The following issues listed since the RC have not been resolved in the official release.
- Using iOS 27.1-specific APIs causes compile errors in Mac Catalyst
- In projects targeting iOS 27.1, the Mac Catalyst run destination does not appear (the workaround is to add a minimum deployment of Mac Catalyst 27.0 in the target settings)
- The first Simulator launch can take several minutes
- In the iPhone Duo simulator, StandBy cannot be used, and most App Extensions cannot be run or debugged
Apps that support Mac Catalyst will still need to separate code with #if !targetEnvironment(macCatalyst).
App Review Guidelines Revised
The App Review Guidelines were revised on October 16, 2026. The main changes are as follows.
- 1.2: Clarified the types of content and apps covered. It now states that failing to implement appropriate safeguards, or failing to correct violations after being notified, may constitute a violation of the Developer Code of Conduct
- 2.3.14: A new guideline on creative assets was added
- 2.5.19: A new guideline prohibiting hidden, dormant, and undocumented features was added. It moves a sentence that was at the beginning of 2.3.1(a), and Apple describes it as a clarification of existing policy. It also states that attempting to hide undocumented features in a binary, such as through code obfuscation, can result in removal from the App Store and suspension of the developer account
- 3.1.1(a): The Music Streaming Services Entitlement section was merged into the StoreKit External Purchase Link Entitlement section, clarifying that you can provide links to permitted destinations
- 5: Clarified that apps that facilitate human trafficking or child exploitation will be removed from the App Store and blocked from alternative distribution
From a maintenance perspective, 2.5.19 is the one that concerns me. Quite a few apps enable features after review through remote configuration or Feature Flags. The policy itself hasn't changed, but with the mention of obfuscation and the penalties now spelled out, I feel there is more room for an app to come under suspicion during review even when it has no intention of hiding anything. The obligation to describe new features specifically in the review notes remains in 2.3.1(a), so I'd like to explain even features toggled by Feature Flags in the review notes.
iOS & iPadOS 27.2 Beta 4 Released
iOS & iPadOS 27.2 Beta 4 (24B5110a) was released on October 13, 2026. Including items not covered in previous articles, the following caught my eye.
- In Health, the redesigned app that could be tried in Beta 3 was removed from Beta 4. Data recorded in the previous beta remains on the device and can be viewed from the Settings app. The redesigned version is expected to be offered again in a future beta
- In StoreKit Testing in Xcode, issues were fixed such as introductory offer eligibility not resetting immediately after calling
SKTestSession.clearTransactions(), and error dialogs appearing on purchase failure even whendialogsDisabledis set totrue - The UIKit change covered in the previous article, where the default layout margins of
UIViewbecome zero on iOS 27.1 and later, is still listed in the Beta 4 release notes
Xcode 27.2 Beta 3 Released
Xcode 27.2 Beta 3 (27B5038j) was released on October 14, 2026. The main changes since Beta 2 are as follows.
- In Interface Builder's
toolchaincompile mode, the issue where standard/systemUIStackView.spacingwas encoded as0and the issue whereUIButtonConfiguration.contentInsetswas not encoded were fixed - An issue where tests using
.rotateDigitalCrowncan fail in XCTest UI Automation was added to Known Issues - The issue where duplicating a 27.2 simulator fails was moved from "General" to the "Simulator Runtimes" section, and a workaround was added
In projects that compile Storyboards or XIBs in toolchain mode, StackView spacing and button content insets may not have been reflected as intended.
The simulator duplication issue is caused by inconsistent file permissions, and the workaround listed is the following command, which deletes the relevant files from the source device's data. The same entry appears in the iOS & iPadOS 27.2 release notes.
find ~/Library/Developer/CoreSimulator/Devices/<SOURCE_UDID>/data -name '*.sb-????????-??????' -delete
The issue where a simulator runtime shows as unavailable after being deleted and reinstalled was moved from Known Issues to the fixed items in Beta 2. The other Known Issues, such as the screenshot problem on iPhone Duo and the compile error when using iOS 27.1 APIs in Mac Catalyst, are unchanged.
iPhone Duo Pre-Orders Begin in Japan Too
Pre-orders for the iPhone Duo began in Japan as well at 9 p.m. JST on October 16, 2026.
Judging from social media, the start looks strong, and shipping appears to be estimated for late January 2027. If you want to secure a device for testing on real hardware, it seems best to order early.
As developers, we need to keep in mind that the OS shipping on launch day is iOS 27.1. The change that makes UIView layout margins zero applies to "iOS 27.1 and later," so the impact is likely to show up on the Duo first, before iOS 27.2 is delivered.
App Store Connect Updates
The App Store Connect release notes had the following updates since the beginning of October.
| Date | Details |
|---|---|
| 10/15 | Apps built with Xcode 27.1 (iOS 27.1 SDK) can now be uploaded to the App Store and TestFlight. Acceptance of iPhone Duo-optimized app submissions and the requirement for Duo screenshots starting in April 2027 were also announced again |
| 10/14 | Apps built with Xcode 27.2 Beta 3 (iOS 27.2 Beta 4 SDK) can now be distributed through TestFlight |
| 10/5 | Creative Assets and the Asset Library were added. You can manage and preview images used for product page headers, search results, and in-app events in one place, together with App Previews and screenshots |
The newly added 2.3.14 in this guideline revision concerns these creative assets. If you use assets, it's a good idea to also check the specifications.
The October Issue of Hello Developer Is Now Available in Japanese
The October issue of Apple Developer's monthly newsletter "Hello Developer" is now available in Japanese as well. The following items in this issue caught my attention as a developer.
- All content in the Apple Developer documentation library is now available in 8 languages, including Japanese (Japanese documentation)
- iPhone Duo-related documentation was added. In addition to documents such as Preparing your app for iPhone Duo, how to choose a camera by orientation, and how to register a camera capture accessory, design kits for Figma and Sketch are also provided
- The first round of the iPhone Duo group labs is available on demand
- Xcode's new project format (a JSON-based
.xcproj) is introduced, and the migration documentation is also available in Japanese - On October 29, an "Ask Apple" event themed on app performance and efficiency will be held in Cupertino. You can also join the livestream
Being able to read the documentation in Japanese should be helpful for sharing with the team and onboarding new members.
Summary
With the official release of Xcode 27.1, there is no longer any need to hesitate between submitting with the RC or waiting for the official release. With less than a week until the iPhone Duo launch, apps planning to support the Duo should be submitted soon.
As for 2.5.19 of the App Review Guidelines, the policy itself hasn't changed, but apps that toggle features with Feature Flags should keep it in mind. The layout margins change will show its impact on the Duo first. The official release date of iOS 27.2 hasn't been announced yet, but once it ships, it will reach existing iPhones as well. Even if you don't plan to support the Duo, it's worth checking in the beta once.
Information surrounding iOS app development changes quickly, so I plan to write another article when notable changes have accumulated.
Job Opening: Classmethod Is Hiring iOS Engineers
The Starbucks Digital Technology department is looking for engineers who can develop iOS apps. We look forward to applications from people who will work with us while sharing all sorts of things 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!