What main actor changes were done in iOS 26?
Asked on 06/11/2025
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In iOS 26, there are several changes related to actors and concurrency, particularly with the introduction of Swift 6. The "Main Actor by default" mode is enabled in new app projects, which provides data race safety without introducing concurrency until you are ready. This is part of the approachable concurrency configuration in Xcode 26. If you want to enable these features in existing projects, you can refer to the Swift Migration Guide. This information is discussed in the session Code-along: Elevate an app with Swift concurrency (02:11).
Additionally, in SwiftUI, views are now implicitly isolated to the main actor by default, meaning if you were explicitly marking your views as main actor, you can now remove that annotation without any change in behavior. This is part of the improvements in Swift 6 language mode, which is opt-in. More details can be found in the session What’s new in SwiftUI (17:18).
What’s new in UIKit
Modernize your app with the latest APIs in UIKit, including enhanced menu bar support, automatic observation tracking, a new UI update method, and improvements to animations. We’ll also cover how you can include SwiftUI scenes in your UIKit app and explore SF Symbols, HDR color pickers, and more.
Code-along: Elevate an app with Swift concurrency
Learn how to optimize your app’s user experience with Swift concurrency as we update an existing sample app. We’ll start with a main-actor app, then gradually introduce asynchronous code as we need to. We’ll use tasks to optimize code running on the main actor, and discover how to parallelize code by offloading work to the background. We’ll explore what data-race safety provides, and work through interpreting and fixing data-race safety errors. Finally, we’ll show how you can make the most out of structured concurrency in the context of an app.
Make your UIKit app more flexible
Find out how your UIKit app can become more flexible on iPhone, iPad, Mac, and Apple Vision Pro by using scenes and container view controllers. Learn to unlock your app’s full potential by transitioning from an app-centric to a scene-based lifecycle, including enhanced window resizing and improved multitasking. Explore enhancements to UISplitViewController, such as interactive column resizing and first-class support for inspector columns. And make your views and controls more adaptive by adopting new layout APIs.