Thread:Project:Support desk/Problem with getting Skins work with most recent media wiki Version/reply (2)

You should really follow the migration guide :)

Or, in your case, don't just download the newest development version of MediaWiki (what is, btw, not the best practice for third-party wikis), download the newest version of the skin as well. So, remove the contents of your skin direcktory (if you don't need them anymore, but at least all PHP files in the root of skins/) and download the newest version of Vector (which isn't bundeled into MediaWiki core anymore, one more thing why a tarball installation is recommended, vector and monobook are still there) from git:

(github)https://github.com/wikimedia/mediawiki-skins-Vector

(wikimedia-git)git clone https://gerrit.wikimedia.org/r/mediawiki/skins/Vector

Now change the require_once line in your LocalSettings.php to match the new path (skins/Vector/Vector.php) and have fun with MW 1.24 :)