Your Wikibase installation will now require you to include its entrypoint. (No change needed for production.) If you didn't already have something like this in your LocalSettings.php you now need to: require_once "$IP/extensions/Wikibase/Wikibase.php"; Or alternatively: require_once "$IP/extensions/Wikibase/repo/Wikibase.php"; require_once "$IP/extensions/Wikibase/client/Wikibase.php"; Change that caused this: https://gerrit.wikimedia.org/r/#/c/217947/ There might be future changes in this area, for switching to https://www.mediawiki.org/wiki/Manual:Extension_registration but those should hopefully be backwards compatible to the above. -- Regards, Jan Zerebecki