Today Joomla team announces availability of Joomla 2.5. Along with new features such as advanced search and automatic notification of Joomla core and extension updates, the Joomla CMS for the first time includes multi-database support with the addition of Microsoft SQL Server.
You can download Joomla 2.5 or Upgrade package from here: www.joomla.org/download.html.
By the way, Joomla 1.7.4 (NEW!) is also available for users who are unable to update to version 2.5.0. It is available here. Please note that version 1.7 will reach end of life on 24 February 2012. Downloading the latest version of Joomla is the best way to ensure company and personal security needs are being met since it will have the most recent updates to protect against the latest security threats.