How to migrate AppDelegate to UISceneDelegate (iOS 26 Requirement)

Apple is transitioning UIKit apps to a scene-based lifecycle, which affects push notifications, starting with iOS 26 and becoming mandatory with iOS 27. Developers are required to adopt UISceneDelegate to ensure their apps launch and continue to support remote notifications, as the traditional AppDelegate lifecycle will no longer suffice. The change, which has been in progress since iOS 13, enables features like iPad multitasking and better background/foreground transitions, ensuring that apps launch correctly and tokens are processed for push notifications. While the core flow of requesting notification permissions and handling device tokens remains unchanged, the integration of UIScene is crucial for maintaining app functionality. Testing on physical devices is recommended due to inconsistent results with simulators, and developers are advised to migrate to the new lifecycle to avoid crashes when building with the iOS 27 SDK. The guide emphasizes that adopting scene support not only future-proofs applications but is essential for continued operation and reliable push notification delivery.