well that used version is actually one year old

its not supported by upstream anymore so it wouldn't hurt updating the wiki also (the extensions used should work when using updated versions)
mediawiki switched to a quarterly release schedule a while back
Tim Starling wrote:Release branches will continue to receive security updates for about a
year from first release, but nonessential bugfixes and feature
developments will be made on the development trunk and appear in the
next quarterly release.
since the year is over (and the wiki is on the initial 1.13 release) an update should be made (im running my wiki from an svn copy anyway so i don't really care, svn up, run the updater and be done with it

)