Thread:Project:Support desk/How to install intl PECL extension?/reply (3)

Its a setting that changes the sort order of categories (See Manual:$wgCategoryCollation) Setting that to uca-default (which is not its default settings) It is the only feature of MediaWiki that requires the intl extension. (The unicode normalization code can use intl extension if installed, which is a little faster than the alternative, but by no means required)