what is new in uikit?

In the "What's new in UIKit" sessions at WWDC, several enhancements and new features were introduced for UIKit:

1. Document Launch Experience: There's a redesigned launch experience for document-based apps, allowing for more control over launch views and support for template document creation. This helps in guiding users in creating their first document while maintaining a great browsing experience.

2. Tabs and Sidebar Updates: Major updates to tabs and sidebars have been introduced, including a new syntax in SwiftUI for tab views to catch common errors at build time. UIKit now has new APIs to better describe app hierarchy to UITabBarController.

3. Fluid Transitions: UIKit now supports new fluid transitions across the system, making the user interface more responsive and delightful.

4. SwiftUI and UIKit Interoperability: Enhancements have been made to improve the interoperability between SwiftUI and UIKit, including the ability to use SwiftUI animation types to animate UIKit views.

5. Automatic Trait Tracking: In iOS 18, UIKit supports automatic trait tracking, making it easier to handle changes in traits without manual registration.

6. UIUpdateLink: A new feature in iOS 18, UIUpdateLink, simplifies implementing complex animations that require periodic UI updates.

7. Apple Pencil Pro and PencilKit: New features for integrating drawing experiences with Apple Pencil Pro, including a squeeze gesture for quick tool switching and an undo slider.

8. New Design System: A vibrant new design system has been introduced, featuring a material called Liquid Glass, which is dynamic and translucent, enhancing the look of system materials and controls.

For more detailed information, you can watch the sessions What's new in UIKit (2024) and What's new in UIKit (2025).