Apple has detailed how iOS 27 was rebuilt to adapt in real time to the iPhone Duo, the company's first foldable iPhone, reshaping the interface as the device folds, unfolds, and switches between its two displays.
Lock Screen controls, the Dock, and app navigation elements now sit along the side of the display instead of across the bottom, freeing up vertical space for content. When open, the iPhone Duo shows two Home Screen pages. The status bar is now a circular, flexible system that fits into the corner of the screen, and the Dynamic Island runs vertically along the side of the outer display.
The interface also changes based on the device's angle. It reorients when the phone is turned on its side and switches to the appropriate display when flipped over. Apple said building this required changing how individual apps lay out content as the screen changes shape, including moving the Dock to a vertical orientation. Controls stay anchored to the side of the screen throughout, and the Lock Screen moves its buttons aside to give more room for the wallpaper.
The iPhone Duo supports side-by-side multitasking, which is a first for the iPhone. Split View lets users run two apps at once, and it's possible to open two windows of the same app, such as Safari, or use Siri AI on one side of the screen while viewing content on the other. Users can swipe up from the bottom to switch apps or save a pair of apps to return to later.
The software also adjusts to how the phone is angled rather than just whether it's open or closed. Content shifts away from the crease when the device is partially folded, where taps are harder to register, and audio tuning algorithms account for the changing distance between the speakers as the phone moves through different positions. When laid flat on a table, iOS uses sensors in each half of the device to let users view content without a stand.
Setting the iPhone Duo down triggers StandBy on whichever display faces up, even when the phone isn't charging, turning it into a photo frame, widget hub, or clock. New Calendar and Weather faces join the existing Clock and Modular options, the Photos face now shows Shared Albums, and each face supports additional colors, fonts, and complications.
Apple has built new APIs for developers to adapt their apps to the dual-display design, and the iPhone Duo support is coming to Device Hub in Xcode. Netflix, Zoom, and Slack have already updated their apps to make use of the larger inner display.
The folding design also enables four camera features not available on other iPhone models. Smart Take uses on-device AI running on the A20 Pro's Neural Engine to analyze a scene and automatically capture a photo when its subjects are posing.
Duo Preview shows a live camera preview on the outer display so a subject can check their framing before taking a shot. Kid Cue plays Peanuts animations on the outer display to get a child's attention. Duo FaceTime lets people standing near the person on a call join in through the outer display.
There are a host of other features such as video playback controls and a keyboard that appear on the lower half of the display when set flat, a split keyboard when the display is partly folded, and more.
Pre-orders for iPhone Duo open at 5 a.m. Pacific on Friday, October 16, with availability beginning Friday, October 23.
