For sitemap
Date("Y-m-d\TH:i:s\+09:00", strtotime($tag_info[$i]['date_created']))
For RSS
Date(\DateTime::RSS, strtotime($post_info[$i]['date_created']))
Overview
Content Tools
For sitemap
Date("Y-m-d\TH:i:s\+09:00", strtotime($tag_info[$i]['date_created']))
For RSS
Date(\DateTime::RSS, strtotime($post_info[$i]['date_created']))