The news
Apple's first foldable iPhone, the iPhone Duo, went on sale on 23 October 2026 in more than 70 countries and regions, including the United States, the United Kingdom, the UAE, France and Germany. Another 28 countries and regions follow on 30 October. Open, it has a 7.6-inch screen that can show two apps, or two Safari windows, side by side. Closed, it has a 5.4-inch outer screen. In the US it starts at $1,999.
Apple tells developers that apps built with its iOS 26 tools or earlier run on the iPhone Duo but do not adapt to it. When the phone is open, such an app appears in the middle of the large screen with empty space around it. When it is closed, the app's content sits to the left of the status bar and camera. To use the whole screen, an app has to be rebuilt with Xcode 27.1 and set up so its layout can change size, because folding or unfolding the phone resizes an app while it is in use.
Apps optimised for the iPhone Duo that include screenshots for it get a badge on their App Store page. Apple names Netflix, Zoom and Slack among the apps already making use of the folding design. From April 2027, every app or game submitted to the App Store must include iPhone Duo screenshots, and iPhone and iPad apps must be built with the iOS 27 SDK or later.
What it means for you
- Customers who buy an iPhone Duo see your app in the middle of the big screen, with empty space around it, until you release an update made for it.
- From April 2027, even a small fix to your iPhone app needs iPhone Duo screenshots and the iOS 27 SDK before the App Store accepts it, so the work belongs in your next release plan.
- Your website will also be seen at new widths, for example in half of the open screen when two windows sit side by side.
What to do now
- Ask your developer whether your app's layout adapts to any screen size, and have it tested in the iPhone Duo simulator in Xcode 27.1.
- Plan an app update before April 2027 that is built with the iOS 27 SDK and comes with iPhone Duo screenshots.
- Open your website in a desktop browser and slowly narrow the window from tablet width to phone width, to check that every size in between still reads well.
How Didset can help
We build iPhone and Android apps whose layouts adapt to every screen size, and we can update an existing app for the iPhone Duo and Apple's April 2027 rules.
Talk to us about it
