iOS 27 enforces stricter adaptivity requirements for UIKit apps, making iPhone apps fully resizable in iPhone Mirroring and on iPad, while introducing new navigation bar minimization controls, sidebar opt-in for iPhone tab bars, and prominent tab customization.
ā¢ UIScene lifecycle is now mandatory ā apps built without it will fail to launch on iOS 27
ā¢ iPhone apps running via iPhone Mirroring or on iPad are now fully resizable, making adaptive layout a hard requirement rather than a best practice
ā¢ UINavigationItem gains barMinimizationBehavior and barMinimizationSafeAreaAdjustment to control interactive scroll-away behavior
ā¢ UITabBarController gains prominentTabIdentifier and sidebar.preferredPlacement = .sidebar for iPhone
ā¢ iPhone apps are now fully resizable in iPhone Mirroring on Mac and when running on iPad ā apps that rely on UIScreen.main, interface orientation, or user interface idiom for layout will break or look wrong
ā¢ Navigation bars gain interactive minimization via barMinimizationBehavior, giving developers explicit control over scroll-away behavior previously only managed by the system
ā¢ iPhone tab bar controllers can now opt into sidebar layout with sidebar.preferredPlacement = .sidebar, unlocking iPad-style navigation on large iPhone contexts
Liquid Glass is Apple's new material and visual design language introduced in iOS 27, bringing translucent, refractive glass-like surfaces to system and custom UI elements. It replaces the frosted vibrancy aesthetic with a more dynamic, depth-aware material that responds to content beneath it.
iOS 27 brings a sweeping set of SwiftUI enhancements including Liquid Glass design adoption, new toolbar visibility and overflow APIs, document architecture improvements with Observable, and resizable iPhone app support ā all designed to modernize app UIs with minimal code changes.
Xcode 27 introduces a fully customizable toolbar and theme system, untitled scratch projects, coding agent integration directly in the editor, and the new Device Hub for evaluating apps across simulators and physical devices side-by-side.
In-depth guide
SwiftUI & Liquid Glass in iOS 27 āPaperKit is Apple's full-featured canvas framework ā previously internal-only ā now publicly available in iOS/macOS/visionOS 27. It powers the drawing and markup experience in Notes, Preview, and Freeform, giving developers access to a complete pencil, shapes, images, and text canvas with a rich data model.