Unity on iPhone Duo

No first-party support. Screen.safeArea works, but mid-session resolution changes and fold-driven lifecycle events need explicit handling.

iPhone Duo goes on sale 23 October 2026, running iOS 27.1. Anything you fix before then, your users never see broken. Start with what breaks first.

Unity iPhone Duo checklist

A Unity game runs on iPhone Duo without changes, but its resolution now changes mid-play, and that breaks assumptions most games make. Here is where common Unity patterns stand.

Unity on iPhone Duo: what works, what breaks

BreaksScreen.width and Screen.height cached in Start()Resolution changes mid-play on fold, unfold and Split View.
WorksA resolution-change check in Update()Rebuild viewports, canvas scalers and render textures on change.
WorksThe Screen.safeArea rectCorrect when used as a rect.
BreaksOne horizontal margin from Screen.safeAreaLeft and right insets differ.
Looks datedLetterboxing to a fixed aspectLarge bands on a 1.42 display; Apple prefers changing the aspect.
WorksA portrait or landscape lockAllowed for games, if the game still fills the screen.
BreaksStopping time in OnApplicationPauseFolding can leave a visibly frozen game on screen.
BreaksInput regions in cached pixelsJoystick bounds and tap zones go stale after a resize.
BreaksCritical HUD in the centre of the inner displaySits on the fold when the device is partly open.
Needs nativeThe hinge (reservedRegions(kind:))No Unity binding; needs a native plugin.

Why games have it harder

Games have a harder problem than apps here, because a game usually renders to a fixed-aspect surface and treats resolution as a launch-time constant.

Resolution changes while running

On iPhone Duo, Screen.width and Screen.height change during play — when the device is folded or unfolded, when the app moves between displays, and when Split View is resized. Anything cached at Start() is stale from that moment.

// Poll for changes rather than caching once
void Update() {
    if (Screen.width != _lastW || Screen.height != _lastH) {
        _lastW = Screen.width; _lastH = Screen.height;
        RebuildLayout();
    }
}

Camera viewport rects, canvas scalers, and any render texture sized from screen dimensions all need recomputing on that event.

Safe area

Screen.safeArea is the right API and it works. The trap is the same as native: code that takes one horizontal inset and applies it to both edges. On iPhone Duo the two differ, so use the rect directly rather than deriving a single margin from it.

Aspect ratio

The inner display is roughly 1.42 — much squarer than the 2.17 most mobile games are tuned for. A game that letterboxes to a fixed aspect will leave large bands; one that extends the camera frustum will show more of the world than the level was designed to reveal. Decide which, deliberately, per scene.

Apple’s design guidelines for iPhone Duo are specific about games. You may lock to portrait or landscape, but the game must fill the screen as the pose changes. Keep text and control sizes as consistent as you can while resizing, and prefer changing the aspect ratio over letterboxing. Where bars cannot be avoided, fill them with artwork so the game still feels full screen.

Lifecycle

Folding the device can move your app between displays without backgrounding it. A game that pauses on OnApplicationPause and resumes only on explicit focus can appear frozen. Test fold and unfold during active play, not just from a menu.

Reserved regions

The hinge division region has no Unity binding. Reaching it requires a native plugin wrapping the Swift API. For most games the practical mitigation is simpler: keep critical HUD elements away from the centre of the inner display, where the fold falls, and use an even number of layout columns so it lands between them.