After Updating from MW 1.36 to 1.37 the following error occurs:
Use of User::getEffectiveGroups was deprecated in MediaWiki 1.35. [Called from MediaWiki\Extensions\Lockdown\Hooks::onGetUserPermissionsErrors in /var/www/html/extensions/Lockdown/src/Hooks.php at line 123] in /var/www/html/includes/debug/MWDebug.php on line 375
The Release Notes for MW 1.35 says:
The following methods of the User class are deprecated: getGroups, getGroupMemberships, getEffectiveGroups, getAutomaticGroups, addGroup, removeGroup, getFormerGroups, getAllGroups, getImplicitGroups, addAutopromoteOnceGroups. Use the new UserGroupManager service instead.
So the extensions seems to be not working anymore.