Apple’s iPhone Duo Tech Talks, in writing

Apple published its iPhone Duo guidance as six videos. Video is a difficult thing to reference while you are actually writing code — you cannot grep it, and you cannot paste an API name out of it. This page says what is in each talk and where the corresponding written detail lives.

These are our summaries, not transcripts. Watch Apple’s videos for the authoritative version — every talk is linked below. Last verified 2026-09-15.

Tech Talk 111466

Design for iPhone Duo

Watch if: You are deciding what the app should look like before writing code.

What it covers

Design for two size classes — compact and regular — rather than a custom layout per pose
Put toolbars, tab bars and controls along the side to free vertical space
Keep interactive elements away from the hinge; scrollable content is the exception
Outer display: offset content so controls do not obscure it
Inner display: use split views and two-column layouts to expose hierarchy
Sheets adapt per pose, and slide clear of the fold

Watch on Apple Why apps look wrong on iPhone Duo

Tech Talk 111461Start here

Prepare your app for iPhone Duo

Watch if: You have an existing app and need to know what breaks. Start here.

What it covers

The three SDK tiers — not built with iOS 27, iOS 27 SDK, iOS 27.1 SDK
Size classes instead of interface orientation; the inner display does not honour orientation locks
Asymmetric safe areas — handle each side independently
UIScreen.main deprecation on two-display devices
ConcentricRectangle and UICornerConfiguration for screen corners
Device Hub in Xcode 27.1, and the App Resizability skill

Watch on Apple Prepare your app: what to fix first The compatibility checklist

Tech Talk 111462

Raise the bar with iPhone Duo

Watch if: Your app has navigation bars, toolbars or a tab bar. So, most apps.

What it covers

Navigation, toolbar and tab bar controls share one vertical region at the side — on the outer display and the inner display in landscape, not the inner display in portrait
axisBehavior: .verticalPreferred and .horizontalOnly
toolbarVerticalEdge / traitCollection.verticalBarEdge for custom views
visibilityPriority and ToolbarOverflowMenu for what survives overflow
toolbarVerticalBehavior(.disabled) to opt a screen out
Custom UIToolbar content is not considered for vertical placement

Watch on Apple UIKit: vertical bars and arrangements Toolbar overflow priorities

Tech Talk 111463

Strike a pose with adaptive layouts on iPhone Duo

Watch if: You need layout that responds to the fold itself.

What it covers

ReservedRegion / UIViewReservedRegion, and the division vs occlusion distinction
Division regions are active only while folded and have zero width when flat
options: .includeInactive to lay out ahead of a fold
ArrangementView and UIArrangementViewController
Split and overlay arrangement styles; overlayArrangementZIndex
Why displacement is a poor fit for continuously scrolling content

Watch on Apple Keep content off the fold Adopt ArrangementView

Tech Talk 111464

Leverage multiple displays and scenes on iPhone Duo

Watch if: You want to use both displays, or support more than one window.

What it covers

onHingeChange and UIHingeInteraction — for interaction and effects, never layout
Hinge states: closed, partially open, fully open
UIApplicationSupportsMultipleScenes — the first iPhone to support multiple instances
New windows only on the inner display; handle UIWindowSceneActivationAction errors
Scene accessories, including the camera capture accessory
All apps participate in Split View multitasking whether they opt in or not

Watch on Apple Support multiple scenes Hinge angle is for interaction, not layout

Tech Talk 111465

Build a great camera experience for iPhone Duo

Watch if: Your app captures photo or video.

What it covers

Two front cameras, both square ultrawide sensors: outer to 4K/120, inner under-display to 1080p/60
Virtual front camera (1080p/60, no depth) vs selecting individual cameras
AVCaptureDeviceDirectionCoordinator — main-actor isolated, in AVKit
AVCaptureDeviceRotationCoordinator, then disable sensor orientation compensation
videoGravity and dynamicAspectRatio for preview layout
A separate direction coordinator for each view when using both displays

Watch on Apple Adopt the direction coordinator Adopt the rotation coordinator

Reading this with an AI assistant?

Every page on this site has a plain-Markdown version at its path plus .md, and the whole corpus is one file at /llms-full.txt — roughly 20,000 words covering the same ground as the six talks, in a format a model can actually read.

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