Thread:Extension talk:Recent Changes Cleanup/Fatal error in RecentChangesCleanup body.php

Hi all, After updating to 1.21 (which I know it says isn't supported fully by this extension yet, so I'm wondering if I've discovered a bug?), I get the following error when I try and access the Special page:
 * Fatal error: Call to undefined function wfLoadExtensionMessages in /home/*****/public_html/wikific/extensions/RecentChangesCleanup/RecentChangesCleanup_body.php on line 10\

Line 10 is the one that reads "wfLoadExtensionMessages('RecentChangesCleanup');" and all I can find about it refers to the possibility of wfLoadExtensionMessages getting replaced or updated with something different in one of the more current MediaWiki releases.

Is there anything that can be done to resolve this, or should I temporarily disable this extension?