Apple today updated its TestFlight and GarageBand apps with support for the iPhone Duo's inner and outer displays. Both apps have the vertical toolbar and will now display properly on the iPhone Duo in any orientation. TestFlight functionality is largely the same with little benefit from the Duo display, but GarageBand gets a wide layout that takes full advantage of the inner screen. It offers up a bigger interface for music editing and using touch instruments like keyboards and guitars.

Apple today highlighted more than 50 third-party App Store apps that are or will soon be fully optimized for the iPhone Duo and its various layouts and poses.

Apple today highlighted more than 50 third-party App Store apps that are or will soon be fully optimized for the iPhone Duo and its various layouts and poses.

In its press release highlighting apps that have been optimized for the iPhone Duo, Apple said the App Store will label apps that are "Made for iPhone Duo". In order for an app to be optimized for the iPhone Duo, the developer needs to build it with the iOS 27.1 SDK or later. Apps optimized for the iPhone Duo fill the entire inner display, and the app's toolbar appears vertically below the status bar.

Apple today updated its Apple Support app to add support for the iPhone Duo and iOS 27.1 (which the Duo ships with). Apple Support will now display properly on the iPhone Duo's wider screen, and it can be used alongside other apps in Split View. iPhone Duo reviews went live today, and poorly sized apps are a recurring complaint among reviewers. Apps that aren't updated for iPhone Duo are letterboxed, with thick black bars on each side.