iPhone Duo app FAQ
Do all iPhone apps work on iPhone Duo?
Yes. Every App Store app runs on iPhone Duo. Apps that have not been rebuilt for it run in a compatibility layout on the inner display, with black borders around an iPhone-shaped window.
What does “letterboxed” mean on iPhone Duo?
The app keeps the shape of a regular iPhone screen and is centered on the 7.6-inch inner display, with black bars on the sides. It works normally but does not use the extra space.
How do developers make an app fit iPhone Duo?
Apps built with Xcode 27.1 and the iOS 27.1 SDK can resize to fill the inner display, move toolbars into the vertical bar and respond to poses such as Book Mode. Apps that use standard split views and tab bars adapt with little extra work.
Can apps use both screens at once?
Only camera apps. With the right entitlement and an active camera session, a camera app can show a preview on the outer display while you use the inner one.
Why isn’t an app on the App Store in my country?
Developers choose where their apps are sold, and some apps aren’t offered in every country or region. App pages here say when an app isn’t on the App Store for the region of the language you’re reading in.
When does iPhone Duo come out?
Apple announced iPhone Duo on September 9, 2026. Preorders started October 16 and it launches October 23 in about 70 countries and regions, with more on October 30.
How can I help?
If you have an iPhone Duo, open any app page and say how well the app fits. You can add a comment and screenshots. If an app is missing, request it, and add your report if you use it.