Thread:Extension talk:User Merge and Delete/MediaWiki 1.15

It says on Extension:User_Merge_and_Delete that "mediawiki 1.13+" is required, but does not work on Debian Squeeze version (1:1.15.5-2squeeze4), it fails with blank page and apache error log: PHP Fatal error: Class 'Html' not found in /var/lib/mediawiki/extensions/UserMerge/UserMerge_body.php on line 150

the solution is to find the older version and use that: svn co http://svn.wikimedia.org/svnroot/mediawiki/branches/REL1_15/extensions/UserMerge

there is link on main wiki which says Warning: Before you download read Requirements or you might install the wrong version:

bur there is no Requirements link, it should be also added and this workaround mentioned