iPhone Duo app development in Singapore
Apple's foldable iPhone Duo went on sale in Singapore on 23 October 2026. Existing iOS apps still run on it, but many sit letterboxed on its 7.6-inch inner screen. We rebuild and adapt your app so it fills both screens, keeps its place through the fold, and is ready for the App Store's iPhone Duo screenshot rule in April 2027.
SleekDigital is a Singapore team for app development in Singapore, building and maintaining iOS, Android and React Native apps.
What changes
What your app looks like on iPhone Duo today
The Duo has a 5.4-inch outer screen and a 7.6-inch inner screen with the same shape, plus Split View for two apps side by side. Apps that were only ever designed for one phone size show it.
Packages
How we update your app for iPhone Duo
Updates start at S$500. What decides the price is how your app is built, not the phone: we review it on both screens first and confirm a fixed price before any work starts.
From S$500
- Rebuild with Xcode 27.1
- Safe area fixes on both screens
- Testing folded, open and in Split View
- iPhone Duo App Store screenshots
Quoted after review
- Everything in Rebuild and badge
- Layouts that follow the available space
- Toolbars and buttons clear of the fold
- Keeping state when the phone opens or closes
Quoted after review
- Two-pane layouts on the inner screen
- Screens that use the half-folded pose
- UI and UX design for both screens
- Release and App Store page update
Not sure which one fits? See what drives the price in our app development cost guide, or send us the App Store link and we will tell you.
App Store
The April 2027 screenshot rule and the iPhone Duo badge
Apple says that starting in April 2027, iPhone Duo screenshots will be required for apps using the iOS 27.1 SDK or later. Apps submitted with iPhone Duo screenshots show a badge on their App Store page telling people they are optimised for the device.
Good screenshots need a layout that looks right on the Duo, so it is worth adapting the app before an update is due, not in the week of a release.
| Screen | Portrait | Landscape |
|---|---|---|
| Outer, 5.4-inch | 1398 x 2034 | 2034 x 1398 |
| Inner, 7.6-inch | 2007 x 2853 | 2853 x 2007 |
Cross-platform apps
Expo, React Native and Flutter apps on iPhone Duo
Cross-platform apps run on iPhone Duo, but neither React Native nor Flutter has an official fold API yet. Using the inner screen properly takes three things: a build on the iOS 27.1 SDK, layouts based on the window size rather than the device, and safe areas read edge by edge, because they are no longer equal on both sides.
Native navigation adapts on its own. Orientation locks do not: the inner screen ignores them. Features that depend on the fold itself, such as a different layout when the phone is half open, need a small native module. Read more about React Native app development in Singapore.
How we work
From review to App Store release
01
Review
We open your app on both screens, folded and open, and tell you which package fits before any work starts.
02
Rebuild
We rebuild the app on the iOS 27.1 SDK, which unlocks the full inner screen.
03
Adapt
Layouts follow the available space instead of the device model, and controls stay clear of the fold.
04
Test
Every key screen is checked folded, open, half-folded, rotated and in Split View.
05
Release
We prepare the iPhone Duo screenshots and submit the update to the App Store.
Need the app redesigned for the bigger screen as well? Our UI and UX design team works on the layouts alongside the developers.
Questions
iPhone Duo app FAQs
Yes, it will open and run. But until it is rebuilt and adapted, it may sit letterboxed on the inner screen, lose its place when the phone folds, or put controls under the fold. From April 2027 App Store submissions will also need iPhone Duo screenshots.
No. iPhone Duo runs the same iOS app. We update your existing app so it adapts to both screens, and the same work also improves it on iPad and in landscape.
Updates start at S$500 for apps that only need a rebuild, fixes and testing. Apps with custom layouts need more work. We review your app first and confirm a fixed price before we start.
Yes. These apps run on iPhone Duo, but they need a build on the iOS 27.1 SDK and layouts based on window size to use the inner screen properly. Fold-specific features need a small native module.
Yes, as long as you have access to the source code and your Apple developer account. We review the code first so there are no surprises.
Next step
Is your app ready for iPhone Duo?
Send us your App Store link. We will check it on both screens and come back with the package that fits and a fixed price.
iPhone and iPhone Duo are trademarks of Apple Inc., registered in the U.S. and other countries. SleekDigital is not affiliated with Apple.