The Joomla Project is pleased to announce the immediate availability of Joomla 2.5.2. This is a security release. The Production Leadership Team's goal is to continue to provide regular, frequent updates to the Joomla community. Learn more about Joomla! developement at the Developer Site.
The update process is very simple, and complete instructions are available here. Note that there are now easier and better ways of updating than FTPing the files.
Please note that you should always backup your site before upgrading.
Release Notes
Check the Joomla 2.5.2 Post-Release FAQs (docs.joomla.org/Category:Version_2.5.2_FAQ) to see if there are important items and helpful hints discovered after the release.