About
A free, community-run list of how iOS apps behave on the foldable iPhone Duo.
Why this exists
On iPhone Duo, an app only uses the whole inner screen once its developer rebuilds it with the iOS 27.1 SDK. Apps built with the iOS 27 SDK fill most of it, and older apps run in a smaller window with empty space around it. Unlike some other foldables, Duo can't fall back to running an app's iPad version, so it's hard to know what you'll get before you try.
This site collects what owners actually see, so you can check the apps you rely on, and developers can see which of their apps people are waiting on.
Statuses
Uses the full inner display with a layout designed for it, and adapts when you fold, unfold or prop the phone half-open.
Uses all or most of the inner display, but with a stretched iPhone layout rather than one designed for Duo.
Runs in a smaller window in the middle of the inner display, with empty space around it. The app hasn't been updated for Duo yet.
Crashes, freezes or is unusable on iPhone Duo.
How the status is decided
Each app's status is the one recent reports agree on. Reports from the last 30 days count, and newer ones count more, because an app update can change everything overnight. Confidence goes up as more reports agree.
Privacy
Reports are anonymous and need no account. We keep a one-way, salted hash of your IP address only to stop duplicate reports and spam. We never store the address itself.
Not affiliated with Apple
This is an independent project. It isn't affiliated with, endorsed by or sponsored by Apple Inc. iPhone is a trademark of Apple Inc. App names and icons belong to their developers and come from the public App Store listing.