iPhone Duo for developers
Two displays, one hinge, and a six-week gap between the specification and the hardware. Every fact below comes with the page it came from, and the two tools are built on nothing else.
Tools
The two displays
| Display | Diagonal | Panel pixels | ppi | Shape | Size class, per Apple |
|---|---|---|---|---|---|
| Outer display (closed) | 5.4″ (5.36″ rect.) | 1398 × 2034 | 460 | 1 : 1.45 | Apple: "The outer display behaves like other iPhone models". |
| Inner display (open) | 7.6″ (7.58″ rect.) | 1878 × 2670 | 430 | 1 : 1.42 | Apple: "the inner display is regular in both dimensions, leaving room for sidebars". |
Apple’s footnote: “The iPhone Duo displays have rounded corners that follow a beautiful curved design, and these corners are within a standard rectangle. When measured as a standard rectangular shape, the screens are 7.58 and 5.36 inches diagonally (actual viewable area is less).” Both panels: ProMotion technology with adaptive refresh rates up to 120Hz. Body 164.6 × 117.8 × 5.2 mm open, 84.1 × 117.8 × 11.3 mm closed, 254 g.
Point sizes: none published. Apple gives pixels and ppi and no scale factor. The outer panel’s 460 ppi sits in the band of Apple’s 3× iPhones and its pixels divide by three; the inner panel is 430 ppi. The circulating point figures are pixels ÷ 3, labelled an inference by their author. This page prints none.
App Store screenshots
| Outer | 1398 × 2034 | 1 : 1.45 |
| Inner | 2007 × 2853 | 1 : 1.42 |
- Not stated as required. Of 18 device cards on Apple’s page, 16 carry a requirement or a scaling note. The Duo card carries neither, and nothing in the fallback chain points at it.
- Inner screenshot ≠ inner panel. 2007 × 2853 is 6.9% larger on each axis than the 1878 × 2670 panel — 14.2% more area. Both numbers are Apple’s; neither page explains it.
- “Consistent” aspect ratio. Apple’s marketing page says so; its spec sheet divides to shapes 2.3% apart. Defensible as a word, not close enough to lay one asset out against both.
- Cannot be uploaded yet. “Support for uploading assets for iPhone Duo in App Store Connect will be available later this year.” App Store Connect
App previews
Apple’s app preview specification has an iPhone Duo row. Accepted resolution 886 × 1920 portrait (the transpose landscape) — the same figure as every current iPhone — in H.264 and ProRes 422 (HQ only), 15–30 seconds at 30 fps.
The row also carries the “later this year” note, so a Duo preview has a published size and no upload path. The mockup tool’s WebM is not one — different format, different size, a frame in the picture.
What Apple says to change in your code
From the Tech Talk Prepare your app for iPhone Duo, verbatim. There is no device family, capability key or plist declaration — the SDK you build against is the only lever Apple documents.
“Your app runs on iPhone Duo even without recompiling, but screen usage improves with each SDK.” “The iOS 27 SDK extends your app left of the status bar on the inner display; the iOS 27.1 SDK reaches the screen edge and lays standard navigation and toolbar buttons out vertically.”
“Don't reference the main screen on a two-display device — it's ambiguous and will be deprecated.”
“The inner display doesn't honor supported interface orientations, so use size classes rather than orientation for layout decisions.”
“Safe areas and layout margins are often asymmetric on iPhone Duo, so handle each side independently and test in Split View.”
“New in iOS 27.1, ReservedRegion in SwiftUI and UIViewReservedRegion in UIKit let custom UI claim as much screen space as possible without colliding with system UI — useful for custom bars and edge-to-edge designs.”
Separately, UIRequiresFullScreen is deprecated as of iOS 26.0 on its own reference page: “Opting out of iPad multitasking and dynamic resizing is deprecated. Use a combination of UISceneSizeRestrictions and prefersInterfaceOrientationLocked to replace some of the behaviors of UIRequiresFullScreen.” And UIScreen.main is marked deprecated in iOS 26.0: “Apple discourages the use of this symbol. Use a UIScreen instance found through context instead. For example, reference the screen that displays a view through the screen property on the window scene managing the window containing the view.”
Is the simulator out? Three Apple statements
- Reads as shipped“Download Xcode 27.1 and run your app in the iPhone Duo simulator using DeviceHub.”Tech Talk
- Reads as not shipped“Xcode 27.1 beta — Coming later this month”Apple Developer
- Reads as not shipped“Latest Xcode entry: Xcode 27 RC (27A266a), September 9, 2026. No Xcode 27.1 beta listed.”Apple Developer
Plan on the two. The Tech Talk’s chapter text is written against a build you may not have. When it lands, Apple says: “Your app runs on iPhone Duo even without recompiling” and the simulator’s controls “let you open, close, rotate, and fold the device to check your layout in every pose.”
Dates
- 9 September 2026Announced; HIG page, Tech Talks and App Store Connect sizes published Apple Newsroom
- 16 September 2026iPhone Duo Group Lab, 8–9 p.m. PT Apple Developer
- 17 September 2026iPhone Duo Group Lab, 8–9 a.m. PT Apple Developer
- 23 September 2026SwiftUI, UIKit and Photos & Camera Q&As Apple Developer
- “Coming later this month”Xcode 27.1 beta with the Duo simulator Apple Developer
- “Coming later this month”"Preparing your app for iPhone Duo" documentation Apple Developer
- 16 October 2026Pre-orders open Apple Newsroom
- 23 October 2026On sale in more than 70 countries and regions Apple Newsroom
- 30 October 2026On sale in 28 more countries and regions Apple Newsroom
- “later this year”App Store Connect accepts Duo screenshots and previews App Store Connect
What Apple has not published
Each absence below was checked, not assumed — the second column says how. This is the list that will be filled in by guesswork over the next month, and the reason this page exists.
| Not published | What was checked |
|---|---|
| Point dimensions or a scale factor for either display | The HIG Layout page’s change log records per-device specifications for every iPhone since 2024 and names the Duo nowhere. The specifications page gives pixels and ppi only. The circulating 626 × 890 and 466 × 678 are pixels ÷ an assumed 3×, labelled an inference by their own author. |
| Whether iPhone Duo screenshots are required, or what happens if you omit them | The Duo card on the screenshot specifications page carries no "Required if…" row and no scaling note; 16 of the other 18 cards carry one or both. Nothing in the iPhone fallback chain points at it. |
| A date App Store Connect will accept Duo assets | Both specification pages say "later this year" and nothing more precise. |
| A device family, capability key, plist declaration or second binary | Eleven Apple pages searched for UIRequiredDeviceCapabilities, UIDeviceFamily, "device capabilit" and "Designed for iPhone": zero hits in every file. Apple’s only lever is the SDK you build against. |
| A deadline by which apps must adopt the iOS 27.1 SDK | Apple’s Get Ready page contains no "deadline", "mandatory", "required by" or "no later than". A date circulating in forums has nothing attached to it. |
| How an app is asked to draw while the hinge is partially open | Apple’s sample tests hinge.status == .partiallyOpen and reads an angle. The HIG describes a folding region that "divides the inner display into multiple usable regions". Neither states what a scene’s bounds are during the fold. |
| What ArrangementView’s .split and .overlay do beyond the Tech Talk’s sample | The "Preparing your app for iPhone Duo" guide is listed as "Coming later this month" on Apple’s Duo developer page. Symbol names on a talk page are not a specification. |
| Any commercial effect of adapting — conversion, ranking, featuring, downloads | Eleven Apple pages searched for "conversion", "convert better", "more downloads", "rank higher", "featured more" and "boost": zero matches. Apple’s two Duo developer surfaces do not mention the App Store. |
| Whether the Duo simulator is available today | Three Apple statements disagree — see the tooling table. Plan on the two that say it is not out. |
Written up on the blog
Questions people type
What are the iPhone Duo screen sizes?
What screenshot sizes does the App Store want for iPhone Duo?
Do I need to update my app for iPhone Duo?
When does iPhone Duo ship?
Is the iPhone Duo simulator available?
What code should I check for iPhone Duo?
About this tool
What has Apple actually published about iPhone Duo for developers?
Apple announced iPhone Duo on 9 September 2026 and published, on the same day, a HIG page, six Tech Talks, a specifications sheet and two App Store Connect specification cards. The device does not reach a customer until 23 October. That six-week gap is where an invented number does the most damage, because nothing can be checked against hardware yet.
This page is every fact from those pages in one place, each with the page it came from — panel pixels, ppi, the two screenshot sizes, the preview row, the dates, the code Apple says to change — and a table of what Apple has not published, with a note of what was checked to establish each absence. Two tools are built on nothing else: a readiness scan over your own source, and a mockup of both displays on a neutral frame.
How it works
- 1Read the displays table for pixels, ppi and shape. There are no point sizes because Apple has published none; the figures circulating are pixels divided by an assumed scale factor.
- 2Read the App Store section for the two screenshot sizes and the preview row, both from App Store Connect’s specification pages. Neither can be uploaded yet, and the screenshot card states no requirement.
- 3Read the code section for the four things Apple’s Tech Talk says to change, verbatim, then run the readiness scan over your project to find them.
- 4Read the tooling table before you plan around the simulator: three Apple statements disagree on whether Xcode 27.1 is out.
- 5Read the "not published" table before you believe a number about the Duo from anywhere, including here.
What it cannot tell you
- Nothing on this page was run on hardware or in a simulator. It is a reading of Apple’s pages on the date shown, re-read rather than recalled.
- It cannot tell you whether adapting to the Duo does anything for your downloads, ranking or conversion. Across eleven Apple pages there is no such claim, and none is made here.
- It cannot tell you what the new APIs do beyond their names. ArrangementView, ReservedRegion and the hinge status appear as symbols on Tech Talk pages; Apple’s guide for them is listed as coming.
- It cannot name the point size of either display, whether Duo screenshots are required, or the date uploads open. Apple has not, so this page does not.
Questions
What is the iPhone Duo screen resolution?
Apple’s specifications give the inner display as 1878 × 2670 pixels at 430 ppi and the outer as 1398 × 2034 at 460 ppi. The inner App Store screenshot size, 2007 × 2853, is a different number from the inner panel, and both are Apple’s.
Are iPhone Duo screenshots required in App Store Connect?
Apple has not said. The Duo card on the screenshot specifications page carries no requirement and no scaling note, unlike 16 of the other 18 device cards. Uploads open "later this year".
Does my app need a new build for iPhone Duo?
Apple states your app runs on iPhone Duo without recompiling and that screen usage improves with each SDK — the iOS 27 SDK widens it on the inner display, the iOS 27.1 SDK reaches the edge and lays bars out vertically. There is no device family, capability key or deadline.
What is the iPhone Duo point size?
Unpublished. Apple gives pixels and ppi and no scale factor. The 626 × 890 and 466 × 678 figures circulating are pixels divided by an assumed 3×, and their own author labelled them an inference.