[Wikitech-l] Removing permissions for the History page

I currently have a set of internal users for our wiki that have Administrator access. I also have a set of external users (our customers) that can only read pages and create discussion pages.

I would like to remove the permission from our customers that allows them to access the History tab. I looked into the Extension:GroupPermissionsManager, but we use PHP 5.3.1 and we plan on upgrading to Mediawiki 1.19 soon, so that doesn't work.

Is there an alternative you recommend? I have removed the history tab from our CSS, but users could still access the direct url of the history page if they wanted. I would like a resolution that denies them access, but still allows myself and other admins to access it.

Thank you,