Thread:Project:Support desk/Error upgrading from 1.21.1 to 1.23.2/reply

Hi!

You are using at least one extension, which calls the hook LoadExtensionSchemaUpdates. This extension does not work correctly with the new version of MediaWiki as it does not provide a valid callback.

The solution is to identify the failing extension and to update it before you run the update script. Most likely an extension update will already solve the issue.