Board Thread:Support Requests - Getting Technical/@comment-25345391-20130521045932/@comment-3335785-20130603004206

Looking through mw:Manual:$wgCategoryCollation, it appears it can't be done with the version of MediaWiki Wikia currently use, 1.19.

That variable was added with 1.21, which may, or may not be updated in the near future. 1.19 looks like it might start being unsupported soon, so who knows.