Pagewren is a SwiftUI app that turns the photos in your camera roll into book pages you can flip through. When iPhone Duo came out on October 23, we wanted the app native on both screens from day one. Most of it just worked. These are the parts that didn't, in case they save you an afternoon.

### 1. Build with the iOS 27.1 SDK, or you're in compatibility mode

Built with the 27.0 SDK, the app ran on Duo in compatibility mode: a little narrower than the screen, with a black strip down the right side. Running natively needs a build from the 27.1 SDK. We submitted from the Xcode 27.1 release candidate, which App Store Connect accepts.

### 2. The outer screen's status bar has its own column

On the outer screen, the status bar sits in a column beside the camera instead of across the top. In our layout that's an 84pt safe-area inset on the right.…