Swift 5.9 Release Process

Swift 5.9 Release Process

This post describes the release process, and estimated schedule for Swift 5.9.

Snapshots of Swift 5.9

Downloadable snapshots of the Swift 5.9 release branch will be posted regularly as part of continuous integration testing. As support is available, snapshot downloads will be added for newly supported platforms.

Once Swift 5.9 is released, the official final builds will also be posted in addition to the snapshots.

Getting Changes into Swift 5.9

On March 20, 2023 the release/5.9 branch will be cut in the swift repository and related project repositories. This will contain the changes that will be released in Swift 5.9. After the branch is cut, changes can be landed on the branch via pull request if they meet the criteria for the release.

Philosophy on Taking Changes into Swift 5.9

  • All language and API changes for Swift 5.9 will go through the Swift Evolution process. Evolution proposals should aim to be completed by the branch date in order to increase their chances of impacting the Swift 5.9 release. Exceptions will be considered on a case-by-case basis, particularly if they tie in with the core goal of the release.
  • Other changes (e.g., bug fixes, diagnostic improvements, SourceKit interface improvements) will be accepted based on their risk and impact.
  • Low-risk test tweaks will also be accepted late into the release branch if it aids in the qualification of the release.
  • As the release converges, the criteria for accepted changes will become increasingly restrictive.

Impacted Repositories

The following repositories will have a release/5.9 branch to track
sources as part of Swift 5.9 release:

The llvm-project and swift-experimental-string-processing will have a corresponding swift/release/5.9 branch.

Release Managers

The overall management of the release will be overseen by the following individuals, who will announce when stricter control of change goes into effect for the Swift 5.9 release as the release converges.

Platform Release Managers

Please feel free to post on the development forum or contact Ted Kremenek directly concerning any questions about the release management process.

Pull Requests for Release Branch

In order for a pull request to be considered for inclusion in the release branch (release/5.9 ) after it has been cut, it must include the following information:

  • Explanation: A description of the issue being fixed or enhancement being made. This can be brief, but it should be clear.
  • Scope: An assessment of the impact/importance of the change. For example, is the change a source-breaking language change, etc.
  • Issue: The GitHub Issue link if the change fixes/implements an issue/enhancement
  • Risk: What is the (specific) risk to the release for taking this change?
  • Testing: What specific testing has been done or needs to be done to further validate any impact of this change?
  • Reviewer: One or more code owners for the impacted components should review the change. Technical review can be delegated by a code owner or otherwise requested as deemed appropriate or useful.

All changes going on the release/5.9 branch must go through pull requests that are accepted by the corresponding release manager.


Hi all – as an update to Mishal’s post above, we are now in the convergence period for Swift 5.9. Further PRs picked to Swift 5.9 should be limited to major showstoppers only – either major new bugs with newly introduced functionality, or regressions in previous features.

Other changes – either enhancements or fixes to long-standing issues – should be landed on main for the next release.



Best wishes for a smooth release process for everyone involved!


We created a new branch release/5.9.0 and it will be accepting extremely limited changes at this point. The release/5.9 branch will be used for future dot releases.


So where does this put Observation?


Observation acceptance will be posted shortly (sorry for the delay). It is already in-tree under a flag so not a concern.


Has this plan been changed again? The release/5.9 branch has been surprisingly active, but github reports only 17 commits made it into the new release/5.9.1 branch in the main compiler frontend repo, with similar results in other Swift repos. In comparison, github reports 332 commits that made it into release/5.9 alone and the Swift version has been bumped to 5.9.2 there last month.

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what happened to 5.9.1? the most recent docker tags available are still on 5.9.0.

The plan for release/5.9.1 is to deliver macros support of Windows platform. This has not been released yet.