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Rebuild against the iOS 27.1 SDK to reach the screen edge

BlockerNeeds iOS 27.1 SDKsdk

What you see

The app runs but is inset from the edge of the inner display, or leaves an unused band beside the status bar.

Start here. Several other fixes on this list are unavailable until you have done this one, because the APIs they use ship in the 27.1 SDK.

The three tiers

Apple described exactly three levels of behaviour in Prepare your app for iPhone Duo:

Built against What your app gets on the inner display
Not the iOS 27 SDK Runs at a familiar size and aspect ratio. It works, but it does not use the display.
iOS 27 SDK Extends left of the status bar area.
iOS 27.1 SDK Extends to the edge of the screen. Standard navigation and toolbar buttons lay out vertically under the status bar.

The important detail is that the first tier is not a failure state. Your existing app will run on iPhone Duo without any changes. Users will not see a crash or a blank screen. What they will see is an app that looks dated next to one that fills the display — which is a competitive problem rather than a functional one, and is the reason this list exists.

The fix

  1. Install Xcode 27.1 or later.
  2. Set the iOS 27.1 SDK as your build target.
  3. Rebuild and run in the iPhone Duo simulator.
  4. Work through the rest of this checklist, because reaching the screen edge means you are now responsible for the geometry at that edge — the hinge, the asymmetric safe areas, and the vertical bars.

Opting into the full-screen experience without doing the layout work behind it can look worse than staying on the previous tier. Treat the SDK bump as the start of the work rather than the whole of it.

Note on availability

As of 9 September 2026 Apple listed Xcode 27.1 beta, the written Preparing your app for iPhone Duo guide, and the iPhone Duo Human Interface Guidelines page as “coming later this month”. If those are not yet downloadable when you read this, the six Tech Talk videos are the authoritative source in the meantime.

How to verify

Run on the inner display and look at the leading edge. Under the 27.1 SDK your content should reach the edge of the screen, and standard bar buttons should appear in a vertical arrangement under the status bar rather than in a horizontal row.

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