Thread:Project:Support desk/updating 'ancient' mediawiki from version 1.4 to 1.19/reply

First make sure you have a backup of the files and of the wiki database.

People often advice you to do it in one go, that means: Replace the old source code with the new one from 1.19 and run the updater in maintenance/update.php. For more information see Update.

Should this not work, this basically can have two reasons: There might be a problem with an extension, which you use. If so, update it. There might be a problem caused by your older MediaWiki version. If so, I would try to do the update in several steps (e.g. going to 1.10 first or so).