iOS 27.2 Beta: What Is New for Developers, Beta by Beta

Apple opened the 27.2 cycle on Wednesday, September 16, 2026, two days after iOS 27.0 shipped, with iOS and iPadOS 27.2 beta (24B5084k), matching macOS, tvOS, visionOS, and watchOS betas, and Xcode 27.2 beta (27B5019j); the second betas followed on Monday, September 21 (iOS 27.2 beta 2, 24B5089g). The iOS notes are short and carry one feature, the expanded App Tracking Transparency prompt for EU users; the Xcode notes carry the change most developers will feel first, a JSON project format, plus a deployment-target bug and a code-completion crash with a workaround; and 27.2 is explicitly not where the iPhone Duo SDK lives. This post reads the notes beta by beta and will grow with each one.¹²³⁵

TL;DR

• Builds. iOS and iPadOS 27.2 beta 24B5084k on September 16 and beta 2 24B5089g on September 21; macOS 27.2 beta 2 26B5091g, tvOS 24K5093g, visionOS 24N5093f, watchOS 24S5091f the same day; Xcode 27.2 beta 27B5019j on September 16 with no second Xcode beta as of September 26.¹
• One iOS feature. “AppTrackingTransparency (ATT) now supports an alternative expanded prompt and re-prompting on a yearly basis for EU users. The alternative prompt is required for users in France, Germany, Italy, Poland, and Romania.” The rest of the iOS notes is three StoreKit Testing fixes, one StoreKit Testing known issue, one Health known issue, and one Shortcuts known issue. No deprecations, no linked-on-27.2 behavior changes.²
• The Xcode change that matters. “Xcode now supports a JSON-based project format (.xcproj) that’s more readable, merge-friendly, and easier for coding agents to edit. Enable it in the file inspector. Projects using .xcproj also open in earlier versions of Xcode 27.”³
• Two Xcode traps. The macOS, watchOS, tvOS, and visionOS SDKs in 27.2 “incorrectly report 27.1 as a valid deployment target,” and Xcode “may crash when using code completion on macOS 27.2 beta,” with a defaults write workaround.³
• Not in 27.2. The iPhone Duo SDK and simulator: “Download Xcode 27.1 beta to get the iOS SDK and simulator support for iPhone Duo,” and Apple’s news post says the phone ships October 23 on iOS 27.1.³⁵

Which build is which?

The order is the story. Apple went to 27.2 betas before any 27.1 beta existed, and then shipped Xcode 27.1 beta two days later as the release that carries iPhone Duo; the Xcode 27 post has the timeline and the Duo simulator post has the hands-on. As of September 26 there is still no iOS 27.1 page in Apple’s release-notes index, only “iOS & iPadOS 27 Release Notes” and “iOS & iPadOS 27.2 Beta 2 Release Notes.”¹²

What do the iOS 27.2 beta notes say?

The page opens with the scope sentence, “The iOS & iPadOS 27.2 SDK provides support to develop apps for iPhone and iPad running iOS & iPadOS 27.2 beta 2. The SDK comes bundled with Xcode 27.2,” and then runs four areas.²

App Tracking Transparency. The one New Feature: “AppTrackingTransparency (ATT) now supports an alternative expanded prompt and re-prompting on a yearly basis for EU users. The alternative prompt is required for users in France, Germany, Italy, Poland, and Romania.” The note names no API. My EU tracking prompt post reads the header and the reference page for what the note leaves out, the new requestTrackingAuthorization overload that buys the expanded sheet in the rest of the EU and the “Additional Information” button that dismisses without recording a decision, and runs a probe on the beta simulator, where every run that prompted, on the first beta’s runtime, showed the standard alert and never the sheet; the sheet itself is a device test, on a device located in the EU and signed in with an EU-region Apple Account.

StoreKit Testing in Xcode. Two entries move from the 27.0 notes’ Known Issues to Resolved: “Changing the storefront or locale using SKTestSession doesn’t propagate through Storefront.updates,” and “Failed purchases using SKTestSession might display error dialogs even when dialogsDisabled is set to true.” A third Resolved entry, “Intro offer eligibility does not reset immediately after calling SKTestSession.clearTransactions(),” repeats a fix the 27.0 notes already list. One new Known Issue: “Making a purchase in-app for a subscription that is a member of a subscription bundle incorrectly allows the user to unbundle instead of throwing an error.”²

Health and Shortcuts. Two Known Issues: “Personalized summaries may not generate as expected in the Insights tab,” and “Describe a Shortcut might fail with the error “Something went wrong. Try again later.””²

That is the whole page. Between beta 1 and beta 2 the sections and radar numbers did not change, per the iOS 27 notes post’s September 21 update; the title and the Overview’s build name did, from “Beta” to “Beta 2.” On the Xcode 27.2 page, the Overview sentence that promised the Duo SDK “later this month in an upcoming release of Xcode 27.1” was replaced by the download aside between September 17 and 19, as the same post records in its September 19 update and footnote 8; the aside is quoted from the current page.³ Every 27.0 deprecation and linked-on-27 behavior change in that post stands unchanged in 27.2 beta 2.²

What does Xcode 27.2 beta change?

The Overview: “Xcode 27.2 beta includes Swift 6.4 and SDKs for iOS 27.2, iPadOS 27.2, tvOS 27.2, watchOS 27.2, macOS 27.2, and visionOS 27.2. Xcode 27.2 beta supports on-device debugging in iOS 17 and later, tvOS 17 and later, watchOS 10 and later, and visionOS. Xcode 27.2 beta requires a Mac running macOS Tahoe 26.6 or later.” Under it sits the aside: “Download Xcode 27.1 beta to get the iOS SDK and simulator support for iPhone Duo.”³

The JSON project format. Under Project Format, New Features: “Xcode now supports a JSON-based project format (.xcproj) that’s more readable, merge-friendly, and easier for coding agents to edit. Enable it in the file inspector. Projects using .xcproj also open in earlier versions of Xcode 27. Learn more in Updating your Xcode project configuration file format.” Three things in three sentences: the format is opt-in per project, it is backward compatible within the 27 line, and Apple names coding agents as a reason. Anyone whose agent has spent turns editing project.pbxproj by regex knows why the coding-agents clause is there; the merge-friendliness is the part teams have wanted for a decade. I have not converted a project yet, so what the file looks like on disk is for a later note.³

The deployment-target trap. Under SDK, Known Issues: “macOS, watchOS, tvOS, and visionOS SDKs in Xcode 27.2 incorrectly report 27.1 as a valid deployment target. Builds and other functionality may have unexpected behavior if this deployment target is used. Mac Catalyst builds with a 27.1 or 27.2 deployment target may be unable to use newly introduced API.” Apple has released no 27.1 for those four systems, and the Xcode 27.1 beta’s own Overview lists their SDKs at 27, so a target set to 27.1 requires an OS version Apple has not shipped. Use 27.0, or 27.2 only for a target meant to require the beta, and keep Apple’s Mac Catalyst caveat in view for both 27.1 and 27.2.³⁶

The code-completion crash. Under General, Known Issues: “Xcode may crash when using code completion on macOS 27.2 beta,” with the workaround defaults write com.apple.dt.Xcode CodeCompletionAssetsToLoad /dev/null, which “turn[s] off enhanced code completion ranking.” The macOS 27.2 beta 2 notes list the crash as fixed on the OS side, so a Mac on beta 2 should not need the default.³⁴

Device Hub and Simulator. Two Device Hub Known Issues: keyboard and mouse input to simulators “for OS versions before iOS 18.0, tvOS 18.0, watchOS 11.0, and visionOS 2.0” is not accepted, and a physical device disconnected while “Simulate Hardware Keyboard” was on “may remain in “hardware keyboard” mode for up to 2 minutes.” One Simulator Known Issue with an old radar: “Some simulator runtimes are not completely deleted when removed, re-appearing after a reboot.”³

Previews. Four fixes, one of them for agents: “The RenderPreview MCP tool now returns the list of available render destinations, and lets the caller specify which destination to use for rendering.” The others are a thumbnail-grid selection bug, a clearer error for unsupported platforms, and a clearer error “when previews fail because another user account on this Mac owns the Previews JIT directory.”³

What do the macOS 27.2 beta 2 notes say?

Five sections. The code-completion crash listed as fixed; one AppKit deprecation, “The EnablePasteboardPrivacyDeveloperPreview user default has been removed”; a Notifications Known Issue on clean installs, where Macs “might not prompt you to allow notifications for some apps, such as Calendar, Maps, Find My, Home, and Weather,” with System Settings as the workaround; the same Shortcuts Known Issue as iOS; and the same StoreKit Testing entries as iOS, three fixed and one new. The macOS 27 notes post covers the 27.0 release the beta builds on.⁴

What is not in 27.2?

iPhone Duo. Apple’s September 16 news post says: “When iPhone Duo becomes available on October 23, it will run iOS 27.1. This version builds on the foundation of iOS 27 and introduces features that were purpose-built for the new foldable design. Xcode 27.1 will add development support for iPhone Duo. This includes updated SDKs and a simulator that supports the all-new poses and orientations of iPhone Duo.” The Xcode 27.2 beta notes repeat the pointer. So a 27.2 beta install tests the EU prompt and the StoreKit fixes; it does not test a fold, and a project that needs both the Duo APIs and the 27.2 SDK is waiting on a build Apple has not published.³⁵

What I would do this week

1. If you sell in the EU, and you must if you sell in France, Germany, Italy, Poland, or Romania, check your tracking flow on a device located in the EU and signed in with an EU-region Apple Account; the simulator showed only the standard alert in my runs, and the EU tracking prompt post has the ship steps and the one return value that is neither a yes nor a no.²
2. Try .xcproj on a branch, not on main: enable it in the file inspector, commit, and see what a merge conflict looks like in the new file before the team adopts it.³
3. Check every target’s deployment menu in Xcode 27.2 for a 27.1 that should not be there on macOS, watchOS, tvOS, and visionOS.³
4. If StoreKit tests around storefront changes or dialogsDisabled were flaky under 27.0, rerun them on 27.2; both causes are listed as fixed.²
5. Keep Xcode 27.1 beta installed beside 27.2 beta if you build for Duo; neither one replaces the other yet.³⁵

FAQ

What is new in iOS 27.2 beta 2?

The same page as beta 1 with a new title and build name in the Overview: the expanded EU App Tracking Transparency prompt, three StoreKit Testing fixes, and three known issues. No deprecations and no behavior changes gated on the 27.2 SDK.²

When will iOS 27.2 be released?

Apple has not announced a date. The betas began September 16 and reached beta 2 on September 21; this post will carry the release when the feed does.¹

Is iPhone Duo supported in the iOS 27.2 beta?

No. The Duo SDK and simulator ship in Xcode 27.1 beta, and the phone runs iOS 27.1 at launch on October 23, per Apple.³⁵

What is the .xcproj format?

A JSON-based Xcode project format introduced in Xcode 27.2 beta, opt-in per project through the file inspector, that Apple describes as “more readable, merge-friendly, and easier for coding agents to edit,” and that earlier versions of Xcode 27 can still open.³

Should I install the 27.2 beta on a device I use?

The notes list the known issues above and nothing about data loss, but the beta is a beta. The EU sheet needs a device located in the EU and signed in with an EU-region Apple Account; the simulator showed only the standard alert in my runs. The StoreKit Testing fixes are listed in the 27.2 OS notes, so a 27.2 simulator runtime should be enough to rerun those tests without a device install.²

Sources