watchOS 4.0

This article summarizes the key developer-related features introduced in watchOS 4.0, which runs on currently shipping watchOS devices. The article also lists the documents that describe new features in more detail.

For late-breaking news and information about known issues, see watchOS 4 Release Notes.

For a complete list of new, modified, and deprecated APIs, see Apple Developer Documentation.

To learn about what’s new in Swift, see Swift in What’s New in Xcode and The Swift Programming Language (Swift 4).

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