Development open for Swift 6.3.1 for Linux and Windows

Development Announcements
1

We are happy to announce the opening of the development phase for Swift 6.3.1.

  • Merge window open: Now
  • Merge window close: April 10th 2026
  • Planned release: End of April 2026
  • Release manager: @mishal_shah (shahmishal on GitHub)
  • Process documentation
  • Changes for Swift version 6.3.1 should be made on the release/6.3.1 branch
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2

@ahoppen Will the high CPU usage by Sourcekit-LSP on Windows be fixed in 6.3.1? The fix was mentioned here: SourceKit-LSP CPU spinning and libdispatch complications - #26 by ahoppen

3

The fix to the spinning issue should be fixed in SourceKit-LSP bundled with Swift 6.4. It’s rewriting the entire stdin parsing logic, so it’s likely too risky to take for a patch release like 6.3.1.

1 Like
4

CC @KushalP regarding the Dispatch fix.
CC @John_McCall

5

I see that 6.3.1 shipped early and there even is a macOS OSS build. Were there any problems with producing the SDK bundles for this release?

Will the 6.3 nightly CI be started up again? I'd like to make sure the Android tests are still passing there.

6

Yes, they are back online.

1 Like
7

Swift 6.3.1 released!

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The release/6.3 branch is currently being used for the 6.3.2 release. If you have changes you’d like to propose for Swift 6.3.2, please cherry-pick the change and target the release/6.3 branch. Changes must be merged before May 1st, 2026.

2 Likes