For iPhone Duo owners
Is your app ready for the big screen?
Apps that haven't been updated for Duo open in a phone-sized window with black bars on the inner display. Check the apps you rely on, and report what you see so others know too.
69 apps tracked · 0 community reports
Where things stand
0 of 69 apps have a report
Recently reported
Questions about apps on iPhone Duo
Why do some apps show black bars on iPhone Duo?
An app only uses the large inner display once its developer rebuilds it for iOS 27. Until then, iPhone Duo runs it in a phone-sized window in the middle of the inner display, with black bars on both sides. This is called letterboxing.
Can iPhone Duo run the iPad version of an app instead?
No. Unlike some other foldable phones, iPhone Duo doesn't fall back to an app's iPad version. Each app needs an update from its developer to use the inner display.
What's the difference between “Built for Duo” and “Fills the screen”?
“Fills the screen” means the app runs full-screen on the inner display but uses a stretched iPhone layout. “Built for Duo” means the app has a layout designed for the inner display, such as a list beside the content, and adapts when you fold or half-fold the phone.
How is an app's status decided?
It comes from reports by iPhone Duo owners. The status is the one most recent reports agree on: only reports from the last 30 days count, and newer ones count more, because an app update can change the answer overnight.
Is this site made by Apple?
No. Is it Duo-ready? is an independent community project and isn't affiliated with or endorsed by Apple Inc.