# Unity on iPhone Duo

> Unity games face resolution changes mid-session on iPhone Duo, plus safe-area and pause-behaviour issues that a fixed-resolution game has never handled.

Source: https://iphoneduosupport.com/frameworks/unity/

Support status: none
No first-party support. Screen.safeArea works, but mid-session resolution changes and fold-driven lifecycle events need explicit handling.
Last verified: 2026-09-09

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Unity has shipped no iPhone Duo support. What follows is our analysis of how a Unity iOS build behaves against Apple's documented behaviours.

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.

```csharp
// 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.

## 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 horizontal centre band of the screen when running on a foldable.

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Published by iPhone Duo Support (https://iphoneduosupport.com). Not affiliated with Apple Inc.