Per the policy mentioned on the project homepage, only the last 2 releases are maintained on a best effort basis. Contrary to this, since releasing Gerrit 3.0.0 there are 4 stable branches that currently still have varying levels of activity: stable-3.0, stable-2.16, stable-2.15 and stable-2.14.
This post clarifies the level of maintenance/support to be expected for the earlier branches.
Extended support for 2.15
Support for 2.15 will be extended, due to the fact that moving forward to 2.16 (and thus migrating to Note DB) is a large step that not all users are able to take so soon.
EOL for 2.14 and earlier
Per the policy, we will bring 2.14 to end of life. This means we do not intend to make any further 2.14.x releases, and changes will not be accepted on the stable-2.14 branch, with the following caveats:
Fixes for critical security issues may be accepted (and new releases made) after discussion among the steering committee and maintainers.
We want to keep the branch buildable with the latest version of Bazel, so related patches will be accepted. We may revisit this decision later depending on the volume of changes.
Branches for earlier releases (stable-2.13 and older) are already inactive and are considered unmaintained. We do not intend to make any new releases from these branches, even for security fixes.
Support for non-core plugins
Plugins will continue to be built for 2.15 on CI, and core maintainers will ensure that they still build, on a best-effort basis.
Plugins will continue to be built for 2.14 on CI, but core maintainers will not put extra effort into keeping the builds working.
Plugins will no longer be built on CI for 2.13 and earlier. Previously built artifacts will be moved to the CI archive.
A separate activity to identify actively used plugins and determine owners/maintainers will follow.