Apple has released Xcode 27.1 beta 1 for developers, enabling app development for the new foldable iPhone Duo. The device launches in October, but the release lets developers prepare for initial support.

Optimizing most apps for iPhone Duo will take weeks. Xcode 27.1 meets Apple's promise to release dev tools before the end of September. Apps built against the iOS 26 SDK need updates for iOS 27 for basic iPhone Duo support. Apps made for iOS 27.1 and later will take full advantage of the larger display. Developers must consider sizing and layout.

Xcode 27.1 beta also offers a simulator to virtually experience apps on iPhone Duo. It is available from Apple's developer webpage. The release follows Xcode 27.2 beta earlier this week.

Apple is shipping iOS 27.2 as the next update for iPhones running iOS 27.0, except iPhone Duo. It will run iOS 27.1, designed for the foldable, before syncing with the lineup later.

iPhone Duo pre-orders start October 16 and ship October 23. Pricing starts at $1999.