wagtail/docs/contributing/release_process.md

Wagtail's release process

Official releases

Release numbering works as follows:

• Versions are numbered in the form A.B or A.B.C.

• A.B is the feature release version number. Each version will be mostly backwards compatible with the previous release. Exceptions to this rule will be listed in the release notes.

• C is the patch release version number, which is incremented for bugfix and security releases. These releases will be 100% backwards-compatible with the previous patch release. The only exception is when a security or data loss issue can't be fixed without breaking backwards-compatibility. If this happens, the release notes will provide detailed upgrade instructions.

• Before a new feature release, we'll make at least one release candidate release. These are of the form A.BrcN, which means the Nth release candidate of version A.B.

In git, each Wagtail release will have a tag indicating its version number. Additionally, each release series has its own branch, called stable/A.B.x, and bugfix/security releases will be issued from those branches.

Feature release

Feature releases (A.B, A.B+1, etc.) happen every three months -- see release schedule for details. These releases will contain new features and improvements to existing features.

Patch release

Patch releases (A.B.C, A.B.C+1, etc.) will be issued as needed, to fix bugs and/or security issues.

These releases will be 100% compatible with the associated feature release, unless this is impossible for security reasons or to prevent data loss. So the answer to "should I upgrade to the latest patch release?" will always be "yes."

Long-term support release

Certain feature releases will be designated as long-term support (LTS) releases. These releases will get security and data loss fixes applied for a guaranteed period of time, typically six months.

Release cadence

Wagtail uses a loose form of semantic versioning. SemVer makes it easier to see at a glance how compatible releases are with each other. It also helps to anticipate when compatibility shims will be removed. It's not a pure form of SemVer as each feature release will continue to have a few documented backwards incompatibilities where a deprecation path isn't possible or not worth the cost.

Deprecation policy

A feature release may deprecate certain features from previous releases. If a feature is deprecated in feature release A.B, it will continue to work in the following version but raise warnings. Features deprecated in release A.B will be removed in the A.B+2 release to ensure deprecations are done over at least 2 feature releases.

So, for example, if we decided to start the deprecation of a function in Wagtail 1.4:

• Wagtail 1.4 will contain a backwards-compatible replica of the function which will raise a RemovedInWagtail16Warning.

• Wagtail 1.5 will still contain the backwards-compatible replica.

• Wagtail 1.6 will remove the feature outright.

The warnings are silent by default. You can turn on display of these warnings with the python -Wd option.

Supported versions

At any moment in time, Wagtail's developer team will support a set of releases to varying levels.

• The current development main will get new features and bug fixes requiring non-trivial refactoring.

• Patches applied to the main branch must also be applied to the last feature release branch, to be released in the next patch release of that feature series, when they fix critical problems:

  • Security issues.

  • Data loss bugs.

  • Crashing bugs.

  • Major functionality bugs in newly-introduced features.

  • Regressions from older versions of Wagtail.

  The rule of thumb is that fixes will be backported to the last feature release for bugs that would have prevented a release in the first place (release blockers).

• Security fixes and data loss bugs will be applied to the current main, the last feature release branch, and any other supported long-term support release branches.

• Documentation fixes generally will be more freely backported to the last release branch. That's because it's highly advantageous to have the docs for the last release be up-to-date and correct, and the risk of introducing regressions is much less of a concern.

As a concrete example, consider a moment in time halfway between the release of Wagtail 1.6 and 1.7. At this point in time:

• Features will be added to main, to be released as Wagtail 1.7.

• Critical bug fixes will be applied to the stable/1.6.x branch, and released as 1.6.1, 1.6.2, etc.

• Security fixes and bug fixes for data loss issues will be applied to main and to the stable/1.6.x and stable/1.4.x (LTS) branches. They will trigger the release of 1.6.1, 1.4.8, etc.

• Documentation fixes will be applied to main, and, if easily backported, to the latest stable branch, 1.6.x.

Supported versions of Django

Each release of Wagtail declares which versions of Django it supports.

Typically, a new Wagtail feature release supports the last long-term support version and all following versions of Django.

For example, consider a moment in time before release of Wagtail 1.5 and after the following releases:

• Django 1.8 (LTS)
• Django 1.9
• Wagtail 1.4 (LTS) - Released before Django 1.10 and supports Django 1.8 and 1.9
• Django 1.10

Wagtail 1.5 will support Django 1.8 (LTS), 1.9, 1.10. Wagtail 1.4 will still support only Django 1.8 (LTS) and 1.9.

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Release schedule

Wagtail uses a time-based release schedule, with feature releases every three months.

After each feature release, the release manager will announce a timeline for the next feature release.

Release cycle

Each release cycle consists of three parts:

Phase one: feature proposal

The first phase of the release process will include figuring out what major features to include in the next version. This should include a good deal of preliminary work on those features -- working code trumps grand design.

Phase two: development

The second part of the release schedule is the "heads-down" working period. Using the roadmap produced at the end of phase one, we'll all work very hard to get everything on it done.

At the end of phase two, any unfinished features will be postponed until the next release.

At this point, the stable/A.B.x branch will be forked from main.

Phase three: bugfixes

The last part of a release cycle is spent fixing bugs -- no new features will be accepted during this time.

Once all known blocking bugs have been addressed, a release candidate will be made available for testing. The final release will usually follow two weeks later, although this period may be extended if the further release blockers are found.

During this phase, committers will be more and more conservative with backports, to avoid introducing regressions. After the release candidate, only release blockers and documentation fixes should be backported.

Developers should avoid adding any new translatable strings after the release candidate - this ensures that translators have the full period between the release candidate and the final release to bring translations up to date. Translations will be re-imported immediately before the final release.

In parallel to this phase, main can receive new features, to be released in the A.B+1 cycle.

Bug-fix releases

After a feature release A.B, the previous release will go into bugfix mode.

The branch for the previous feature release stable/A.B-1.x will include bugfixes. Critical bugs fixed on main must also be fixed on the bugfix branch; this means that commits need to cleanly separate bug fixes from feature additions. The developer who commits a fix to main will be responsible for also applying the fix to the current bugfix branch.