Chrome Release Cycle

Upcoming Changes

Chrome is planning to transition to a four week release cycle in Q3 2021; you can read more about the new release cycle here. The information below is still relevant until the new cycle is live, at which point this page will be replaced by the content at the link above.

Overview

Chrome pushes a new stable version to the public every 6 weeks while taking 7 weeks to stabilize the beta branch.

Schedule

Schedule

  • Feature freeze and branch point dates are fixed, but release dates may change depending on the build quality.
  • There would be some adjustment in the release schedule due to Chrome no meeting weeks or holidays.

Key Dates

Feature Freeze

2 weeks before the branch point, the feature freeze is declared! Any feature planned to launch with this milestone should be code-complete (its implementation should be done) and enabled on Trunk/Canary so that the test team can give initial feedback. By the feature freeze, all strings must be landed!

Branch Point

Every 6 weeks, the latest canary is declared as the new milestone stabilization branch with a number (used as the branch name) associated with it. The feature enhancement should be completed by the branch point and all ReleaseBlock-Beta bugs should be fixed. Avoid committing big and risky changes close to the branch point!

First Beta

2 weeks after the branch point, the first beta release is pushed. All disabled tests associated with the release milestone should be completely addressed. New beta builds are pushed weekly until the stable release.

Stable Cut

The Thursday before the stable release date, the last build from the beta branch is cut as the release build. All ReleaseBlock-Stable bugs should be fixed by the stable cut, which consequently corresponds to the absolute last date a merge to the release branch should be taken for inclusion in the initial stable release. The stable cut will, unless there are exceptions, use the final beta as its basis. For Chrome OS, the stable cut date may be different than the rest of Chrome.

Stable Release

7 weeks after the branch point a new major version is released. The stable rollout is staged over time so that any issues can be detected early and addressed before they reach all users. Each Chrome platform has a different stable rollout plan and the schedule below can vary based on circumstances:

  • Desktop: Desktop consists of three main platforms, Windows, Mac, and Linux. Linux is ramped up to 100% immediately. Mac and Windows follow a staged rollout as follows:
    • 5% deployment ->15% deployment ->50% deployment ->100% deployment.
  • Android: Android releases both Chrome and WebView with each release, and follows a pattern similar to:
    • 1% deployment -> 5% deployment -> 10% deployment -> 50% deployment -> 100% deployment.
  • iOS: iOS follows a phased release with no control over the following rollout percentage schedule:
    • Day 1: 1% -> Day 2: 2% -> Day 3: 5% -> Day 4: 10% -> Day 5: 20% -> Day 6: 50% -> Day 7: 100%.

Stable Refresh

A stable refresh is defined as a release of a new Chrome build outside of the normal release schedule to fix critical bugs detected during the stable rollout. Except for extremely critical issues (e.g. security or privacy escalations), a Chrome stable refresh should not be pushed more than 2 weeks after the initial build has been released to the public. In this case, we should consider punting any detected production issues to the next release.

More Info

For more information, see these guidelines for considering branch dates in project planning.