Hi all, you can now declare in the extension infobox what compatibility policy is being followed. Most extensions follow one of two policies: * The master branch of the extension should remain compatible with older versions of MediaWiki core (supported versions, maybe even older ones). Developers updating the extension after a core change are expected to leave B/C code so that the extension keeps working with both versions of core. Users of the extension should use the master branch no matter what core version they are running (unless it is really old, in which case they are on their own). * Extension release branches (REL1_XX branches, which are created automatically if the extension is hosted on gerrit) are compatible with matching core branches. Developers updating the extension after a core change are free to remove old logic, but should backport security fixes to supported branches. Users of the extension should use master with MediaWiki master, and the corresponding branch with a MediaWiki release (e.g. the REL1_27 extension branch if they use MediaWiki 1.27). For extensions you maintain, please add the right template parameter to {{Extension}}: |compatibility policy = master or |compatibility policy = rel This will be a great help to developers who are doing mass extension changes after a breaking core change. For more details, see https://phabricator.wikimedia.org/T156500