iPhone Duo Developer Resources
Official Apple documentation, videos, design resources, and tools for iPhone Duo development, organized in one place.
Last updated
Quick answer
Watch all six official iPhone Duo Tech Talks in this order: Design (111466), Prepare (111461), Vertical Bars (111462), Adaptive Layouts (111463), Multiple Displays (111464), then Camera (111465); they map to DuoReady /design, /getting-started and /checklist, /vertical-bars, /adaptive-layout and /arrangementview, /multiple-displays, and /camera.
Start at the hub, watch the six Tech Talks in order, then keep the HIG and Device Hub open while you implement. Environment: Xcode 27.1 beta + iOS 27.1 SDK. For coding agents, start with Apple's App Resizability skill, then the unofficial pack listed under AI coding.
Start here
Get ready for iPhone Duo
Primary hub: videos, HIG, Xcode, design kits, workshops, and Q&A.
Build for iPhone Duo with new resources
Apple Developer News — Xcode 27.1 SDK and September 18 design kits.
Tech Talks index
All six Duo talks, about 71 minutes total.
Developer Forums
Ask Apple engineers during the Duo Q&A sessions.
Official videos
Watch order: Design → Prepare → Vertical Bars → Adaptive Layout → Multiple Displays → Camera.
Talk-to-guide map: Design 111466 → /design · Prepare 111461 → /getting-started, /checklist · Vertical bars 111462 → /vertical-bars · Adaptive layouts 111463 → /adaptive-layout, /arrangementview · Multiple displays 111464 → /multiple-displays · Camera 111465 → /camera.
HIG and design kits
Designing for iPhone Duo
Dedicated HIG: poses, reserved regions, fold avoidance, vertical bars.
Human Interface Guidelines
Full HIG, including updated layout guidance.
What’s new in Design
September 9 Designing for iPhone Duo HIG addition.
Apple Design Resources
iPhone Duo Figma / Sketch kits and product bezels.
Tools and specs
Xcode 27.1 beta
Download the iOS 27.1 SDK and Duo Simulator.
Xcode
Device Hub: open, close, rotate, fold, Split View, both displays.
Xcode documentation
Simulator and Device Hub reference.
iPhone Duo Technical Specifications
Inner 7.6″ 1878×2670 · Outer 5.4″ 1398×2034.
Xcode 27.1 Release Notes
Duo Simulator, Previews Display picker, first-launch delay, known issues.
App Store screenshot specifications
iPhone Duo outer 1398×2034 · inner 2007×2853. Upload later this year.
AI coding
App Resizability skill (Xcode 27.1)
Xcode 27.1 ships Apple's App Resizability skill with SwiftUI and iPhone Duo guidance. You do not need to find the skill file first. Tell the agent to locate and read the built-in skill, then audit the current project. Background: Modernize your UIKit app (WWDC26).
- Adaptive Layout
- Size Classes
- Safe Area
- UIScreen
- Orientation
- Scene Lifecycle
- iPhone Duo dynamic sizes
- Asymmetric safe area
- 1Install Xcode 27.1 beta
- 2Have the agent read the built-in App Resizability skill
- 3Audit the existing SwiftUI / UIKit project
- 4Create an `iphone-duo` branch
- 5Test in the Duo Simulator
- 6Fix only real compatibility issues
Common mistake
Do not ship a Duo-only UI before the audit. Let the agent follow Apple's skill, then test in the Duo Simulator and fix only what actually breaks. Setup: How to Test Your App on iPhone Duo with Xcode 27.1.
I installed Xcode 27.1 beta. It includes the iPhone Duo Simulator
and a new agent skill for iPhone Duo layout adaptation.
Find Xcode's built-in App Resizability skill and read it.
Use its iPhone Duo / SwiftUI guidance to audit this project.
Then create an `iphone-duo` branch and do debug and adaptation
work only on that branch.
Prefer real compatibility issues.
Do not rewrite the existing UI just for iPhone Duo.To use the same skill outside Xcode, export Apple's bundled skills first:
xcrun agent skills exportiPhone Duo Skills (unofficial)
Third-party pack — not from Apple. Nine extra agent skills for Claude Code, Cursor, Copilot, Gemini, and similar tools.
iPhone Duo Skills
GitHub: 9 agent skills for iPhone Duo readiness, layout, bars, hinge, camera, design review, games, Flutter, and React Native.
npx skills add mirzaaghazadeh/iphone-duo-skillsiphone-duo-readinessiphone-duo-adaptive-layoutiphone-duo-vertical-barsiphone-duo-hinge-and-scenesiphone-duo-cameraiphone-duo-design-reviewiphone-duo-gamesiphone-duo-flutteriphone-duo-react-native
Apple Q&A · September 23
Frequently asked questions
Which of the six iPhone Duo Tech Talks should I watch, and in what order?
Watch all six official talks in this order: Design for iPhone Duo (111466), Prepare your app for iPhone Duo (111461), Raise the bar with iPhone Duo (111462, vertical bars), Strike a pose with adaptive layouts (111463), Leverage multiple displays and scenes (111464), then Build a great camera experience (111465). Start from the Tech Talks index at tech talks — about 71 minutes total.
How do the six Tech Talks map to DuoReady guides?
Design for iPhone Duo (Tech Talk 111466) maps to /design. Prepare your app (Tech Talk 111461) maps to /getting-started and /checklist. Raise the bar / vertical bars (Tech Talk 111462) maps to /vertical-bars. Adaptive layouts (Tech Talk 111463) maps to /adaptive-layout and /arrangementview. Multiple displays (Tech Talk 111464) maps to /multiple-displays. Camera (Tech Talk 111465) maps to /camera.
What is the App Resizability skill in Xcode 27.1?
Xcode 27.1 includes Apple’s App Resizability agent skill with SwiftUI and iPhone Duo guidance. Use it to audit adaptive layout, size classes, safe area, UIScreen, orientation, scene lifecycle, Duo dynamic sizes, and asymmetric safe area. Do not hunt the skill file yourself — tell the agent to find and read the built-in skill. Export it for other tools with xcrun agent skills export. Background: WWDC26 Modernize your UIKit app at 278.
How should I ask a coding agent to use the App Resizability skill?
Tell the agent you installed Xcode 27.1 beta with the Duo Simulator and the App Resizability skill, then ask it to find and read that built-in skill, audit the current project, create an iphone-duo branch, and fix only real compatibility issues — do not rewrite the existing UI just for iPhone Duo. Copy the agent-prompt block on this page.
How do I add iPhone Duo skills to Cursor or Claude Code?
Start with Apple’s App Resizability skill from Xcode 27.1 (xcrun agent skills export). For extra unofficial Duo coverage, run npx skills add mirzaaghazadeh/iphone-duo-skills to install the third-party iPhone Duo Skills pack (9 agent skills) from mirzaaghazadeh/iphone-duo-skills. It works with Claude Code, Cursor, Copilot, Gemini, and similar agents. That pack is not an Apple product.