Joomla! is a feature-rich open-source Content Management System (CMS). Joomla 1.5.x is not just a common update of the current Joomla version it is a completely rebuild, redesigned and improved CMS. It keeps legacy support for all features of joomla 1.1.x but in addition it provides simplified content and modules control, improved templates, object-oriented pattern based API with support for both php4 and php5.