How to migrate my app from AppDelegate to UIScene

To migrate your app from AppDelegate to UIScene, you should adopt the UI Scene lifecycle, which is becoming mandatory in future iOS releases. Here are some steps and considerations based on the sessions from WWDC:

Adopt UI Scene Lifecycle: Starting with iOS 26, any UIKit app built with the latest SDK will be required to use the UI Scene lifecycle. This means that the traditional AppDelegate methods will be deprecated, and you will need to implement scene-based lifecycle methods.
Scene Configuration: In your AppDelegate, you will need to determine the scene configuration for a connecting session. This involves implementing the application(_:configurationForConnecting:options:) method to return a UISceneConfiguration object.
Scene Delegate: Each scene in your app will have its own SceneDelegate that manages the lifecycle of that scene. You will need to implement methods such as scene(_:willConnectTo:options:) to set up your scene's initial UI and state.
State Restoration: Scenes independently save and restore their UI state. You can handle state restoration by implementing methods like scene(_:restoreInteractionStateWith:) in your SceneDelegate.
Mixing SwiftUI and UIKit: You can now mix SwiftUI and UIKit scene types in a single app, which provides flexibility and allows you to leverage the strengths of both frameworks.

For more detailed guidance, you can refer to the session Make your UIKit app more flexible (00:58) and What’s new in UIKit (17:45) which cover the adoption of the UI Scene lifecycle and its benefits.