Notes, resources, and discoveries from the iPhone Duo Group Lab.
Exploring what’s next for layouts, multitasking, and camera experiences.
Questions, advice, and discussion with Apple engineers and designers about creating and updating apps for iPhone Duo.
Open the group lab alongside this journal to follow the conversation and refer back to your questions and code examples.
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Adapting layouts as the available space and device pose change.
Understanding how the hinge should influence content and interaction.
Keeping an app useful and comfortable as it shares the display.
Building camera experiences that feel natural in different configurations.
Apple has announced Duo SDK and Simulator support for later this month, with no exact date yet. The simulator will support Duo’s poses and orientations.
iPhone Duo launches October 23 with iOS 27.1.
Apple’s availability announcement ↗Includes Swift 6.4, the 27.2 platform SDKs, and a JSON-based .xcproj project format. Requires macOS Tahoe 26.6 or later.
Duo support is still pending: these release notes point to the upcoming Xcode 27.1 release for its SDK and simulator.
Features and known issues ↗For Duo-specific testing, watch for Xcode 27.1 beta. You can explore the general layout examples below in the meantime. Check Apple’s downloads ↗
Three independent SwiftUI examples. In an iOS app project, replace ContentView.swift with one example, then open the Xcode preview or run in Simulator. This journal targets iPhone Duo on iOS 27.1 or later. Duo-specific Simulator testing requires the upcoming Xcode 27.1 beta.
Switch from a row to a column when the content no longer fits.
import SwiftUI
struct ContentView: View {
var body: some View {
ViewThatFits(in: .horizontal) {
HStack { actions }
VStack { actions }
}
.buttonStyle(.bordered)
.padding()
}
@ViewBuilder
private var actions: some View {
Button("Save to reading list") { }
Button("Share this discovery") { }
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
Try this : Narrow the preview or increase the text size. The buttons stack vertically.
Choose a stack using the horizontal size class, while keeping the same child view.
import SwiftUI
struct ContentView: View {
@Environment(\.horizontalSizeClass) private var sizeClass
@State private var note = ""
var body: some View {
let layout = sizeClass == .regular
? AnyLayout(HStackLayout(spacing: 24))
: AnyLayout(VStackLayout(spacing: 24))
layout {
Text("Lab notes")
.font(.title)
TextField("One thing I learned", text: $note)
.textFieldStyle(.roundedBorder)
}
.padding()
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
Try this : Type a note, then change the preview between compact and regular width. The note stays.
Show a sidebar and detail when space allows, with a navigation stack in compact layouts.
import SwiftUI
struct ContentView: View {
private let topics = ["Layouts", "Multitasking", "Camera"]
@State private var selection: String?
var body: some View {
NavigationSplitView {
List(topics, id: \.self, selection: $selection) { topic in
NavigationLink(topic, value: topic)
}
.navigationTitle("Topics")
} detail: {
Text(selection ?? "Choose a topic")
.font(.title)
.padding()
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
Try this : Select a topic, then try a narrow and a wide preview. This is navigation inside one app, not two-app Split View.
These examples teach adaptive layout fundamentals. They do not use Duo-specific hinge or camera APIs. The first example’s buttons demonstrate layout only.
Collected from Apple Developer on September 16, 2026. The hub also lists upcoming workshops, Q&As, and tools as they become available.
For an app that already supports iPhone and iPad, should we treat iPhone Duo primarily as another adaptive size-class environment, or are there scenarios where Apple recommends implementing Duo-specific layouts?
Focus on making the app adaptable. Build on the work already done for iPad, then layer in the newer APIs and additions, such as vertical controls.
Paraphrased from Marc’s live notes; not a verbatim quote.
Can the Duo be in seated mode with the camera side face down on the table, or only outer-screen down? If so, is it possible to detect which screen is face upwards vs forwards?
Seated mode should work either way: with the camera side down or with the outer screen down. The panel was not sure whether an app can detect which screen faces upward versus forward. Detection remains unconfirmed.
Paraphrased from Marc’s live notes; not a verbatim quote.
Will a custom tab bar displayed at the bottom of the interface automatically adapt to iPhone Duo? How will it be displayed?
The panel strongly recommends moving from a custom tab bar to the standard system tab bar. The response recorded here did not confirm whether a custom bottom bar adapts automatically or how it would be displayed.
The panel also shared that Apple had wanted to introduce vertical bars for a long time, but had not had a layout where they made sense until iPhone Duo.
Paraphrased from Marc’s live notes; not a verbatim quote.
What is one thing you'd want all developers to adapt properly for the best experience?
Paraphrased from Marc’s live notes; not a verbatim quote.
Start with an adaptable app, build on existing iPad support, and layer in the newer APIs. The first panel answer is recorded above.
Notes in progress