In its press release highlighting apps optimized for the iPhone Duo, Apple said the App Store will label apps that are "Made for iPhone Duo."
To be optimized for the iPhone Duo, a developer must build the app with the iOS 27.1 SDK or later. Optimized apps fill the entire inner display, and the app's toolbar appears vertically below the status bar. Apps built with the iOS 27 SDK fill most of the inner display but still avoid the status bar on the right edge. Apps built with the iOS 26 SDK or earlier run on the iPhone Duo, but they appear in the center of the inner display with lots of empty space on each side.
Many more apps are being optimized for the iPhone Duo each day, so users should keep a close eye on the App Store's updates menu.
iPhone Duo launches this Friday. Apple retail staff have reportedly been told to warn customers against visiting stores to buy an iPhone Duo without a pre-order, as there will likely be no stock available for walk-in purchases on launch day.
Source: MacRumors · Summarized by HeadlinesBriefing