Slicing is the process of creating and delivering variants of the app bundle for different target devices. A variant contains only the executable architecture and resources that are needed for the target device. You continue to develop and upload full versions of your app to iTunes Connect. The App Store will create and deliver different variants based on the devices your app supports. Image resources are sliced according to their resolution and device family. GPU resources are sliced according to device capabilities. For tvOS apps, assets in catalogs shared between iOS and tvOS targets are sliced and large app icons are removed. When the user installs an app, a variant for the user’s device is downloaded and installed.
Xcode simulates slicing during development so you can create and test variants locally. Xcode slices your app when you build and run your app on a device. When you create an archive, Xcode includes the full version of your app but allows you to export variants from the archive.
Sliced apps are supported on devices running iOS and tvOS 9.0 and later; otherwise, the App Store delivers universal apps to customers.