WWDC26 - Apple OS 27 releases

OS 27 Field Notes

Short developer notes for Apple's OS 27 releases announced at WWDC26, focused on changes that affect app code.

Updated June 15, 2026 WWDC26 2 available posts

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WWDC26 SwiftData session artwork
01 6 minute read WWDC26 session 274

What's New in SwiftData

Sectioned fetches, codable attributes, and model-store observers for app code that lives outside SwiftUI views.

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WWDC26 Swift session artwork
02 7 minute read WWDC26 session 262

What's New in Swift

Swift 6.4 availability syntax, async cleanup, Testing migration, Foundation speedups, and measured performance tools.

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Covered scope

Apple OS 27 and WWDC26 developer notes.

The index is for practical notes across iOS 27, iPadOS 27, macOS 27, watchOS 27, tvOS 27, visionOS 27, SwiftData, Swift 6.4, and shared Apple SDK changes.

iOS 27 iPadOS 27 macOS 27 watchOS 27 tvOS 27 visionOS 27 WWDC26 WWDC 2026 SwiftData Swift 6.4