Readiness audit
We run your app in the iPhone Duo simulator in Xcode, folded and unfolded, and report every screen that clips, letterboxes, hides content under the fold or camera, or loses state when the device opens.
Service · iPhone Duo App Adaptation
Get your iOS app ready for iPhone Duo, Apple's foldable.
iPhone Duo goes on sale on 23 October with a 7.6-inch inner display. We audit how your app behaves when it unfolds, design the larger layouts and ship the SwiftUI or UIKit changes, so it looks made for the device rather than stretched onto it.
150+
shipped projects
$32M+
raised by clients
9,000+
tasks delivered
Direct answer
Adapting an app for iPhone Duo means making it work on both screens: the small cover display and the 7.6-inch inner display it unfolds into.
Apple asks apps to lay out by size class rather than by device or orientation, and to stay clear of the fold and camera through its reserved regions APIs. Apps built with older versions of Xcode do not extend beneath the status bar and camera areas. We find where your app breaks, design what the inner display should show, and build it.
What we do
Three steps from a stretched app to one that uses the fold.
Each step can be ordered on its own. Most teams start with the audit and decide from there.
Design for the inner display
Layouts that use the 7.6-inch screen: two-column and split views, list-and-detail navigation, and larger content areas, while the cover display keeps a normal iPhone layout.
SwiftUI and UIKit build
Size-class driven layouts, NavigationSplitView where it fits, reserved regions for the fold and camera, and state that survives folding and unfolding, built with the Xcode release that supports Duo.
Testing and release
Folded, unfolded and rotated states checked in the simulator, regression checks on standard iPhones, and an App Store update with screenshots that show the larger display.
Best fit
Worth doing if your app should look native on Apple's most expensive iPhone.
Your users buy new Apple hardware
At $1,999, iPhone Duo is the most expensive iPhone yet. The people who buy it are the users you least want to see a stretched or letterboxed app.
Your app is content- or work-heavy
Lists with detail views, dashboards, reading, shopping, maps and editors gain the most from a second column on the inner display.
Your layouts assume a fixed screen
Code that reads the screen size, the device idiom or the orientation is what Apple tells developers to replace. We find it and move it to size classes.
You want a clear answer before you spend
Start with the audit. You get a list of what breaks and what it takes to fix, and decide whether to adapt now or later.
Process
From an audit to an App Store update.
The audit sets the scope. Design and build only cover what your app actually needs on the larger display.
Audit in the simulator
Folded, unfolded and rotated runs of your key flows, with a written list of issues and their fix.
Decide the inner-display layout
Which screens get two columns, a split view or more content, and which simply grow.
Build and test
SwiftUI or UIKit changes, reserved regions, state handling, and regression checks on standard iPhones.
Ship the update
App Store build and new screenshots for the larger display.
Related work
iOS apps we build, ship and run ourselves.
Our own products on Apple platforms, built natively in SwiftUI: a live App Store app with widgets, a world clock for iPhone, Mac and Apple Watch, and an AI camera for iPhone.
iOS App · Widgets
My Chess Rating our own iOS app
Our own iPhone app and home-screen widget that puts Chess.com and Lichess ratings in one place and explains why they move: tilt check, best hours, openings that cost points, goals and a Sunday report. SwiftUI, WidgetKit and StoreKit 2 on a Node and Postgres backend, designed, shipped and run by 99 Francs.
Mobile App · iOS, Android, Mac, Watch
Timeslide our own world clock
Our own world clock where every city is a card: drag one sideways and a single shared time moves across all of them, with the weather for that hour. Built natively for iPhone, Android, Mac and Apple Watch, with widgets, GPU weather shaders and 8 languages. On Google Play; the iPhone app is in beta.
Mobile App · AI
ClearShot our own AI camera
Our own iPhone camera that removes tourists and strangers from travel photos in one tap, or keeps just the person you choose. People are found on the phone with Vision, a cloud model repaints only inside that mask, and a Node and Postgres backend charges only for results. iPhone and Android, in review on both stores.
iPhone Duo
Find out how your app looks when it unfolds.
Send the App Store link. We start with the audit and tell you what it takes before any build work.
Discuss a Duo adaptation→iPhone Duo is Apple's first foldable iPhone, announced on 9 September 2026 and on sale from 23 October, from $1,999. It has a smaller cover display and opens to a 7.6-inch inner display, and it supports split screen and Apple Pencil.
It will run, but it may not look right. Apps built with older versions of Xcode do not extend beneath the status bar and camera areas, and layouts that assume a fixed iPhone screen size can leave the inner display poorly used. The audit shows exactly what happens in your app.
Apple's guidance is to lay out by size class instead of the device idiom, the orientation or the main screen bounds, to use standard containers such as stacks and NavigationSplitView, and to avoid the fold and camera with the reserved regions APIs in SwiftUI and UIKit.
The device goes on sale on 23 October, so no app has a long Duo track record yet, including ours. What we bring is native iOS work on our own apps — My Chess Rating, Timeslide and ClearShot, built in SwiftUI for several screen sizes — and an audit that starts in Apple's iPhone Duo simulator in Xcode.
It depends on how many screens need a new layout, which the audit shows. Tell us about the app and we will reply with an estimate. New iOS apps are covered on our iOS app development page.