Swift 6.4 Released

Swift 6.4 was released on September 10, 2026, bringing a suite of performance improvements, bug fixes, and a handful of new language features to the Apple‑backed open‑source compiler. The update tightens the concurrency model, adds several new standard‑library APIs, and expands the Swift Package Manager’s support for binary dependencies. Compatibility with the latest Xcode 16 and macOS 14, iOS 17, watchOS 10, and tvOS 17 is maintained, and the release includes updated documentation and migration guides for developers moving from Swift 6.3.

The Swift team highlighted that Swift 6.4 focuses on stability and developer ergonomics, with a particular emphasis on reducing compile times and memory usage for large projects. Minor changes to the type‑inference system and the introduction of new compiler diagnostics help catch common mistakes earlier in the build process. The release also contains a number of security patches and updates to the LLVM backend, ensuring that Swift binaries remain efficient across Apple’s hardware platforms.

Swift 6.4 is available for download from the official Swift website and can be installed via Homebrew or the Swift Package Manager. The announcement has generated discussion on Hacker News, where the post received 98 points and 39 comments, indicating active interest from the developer community. The Swift Foundation encourages teams to test the new release in their build pipelines and to report any regressions to help refine future updates.