The current version is Joomla! 3.3.3. If you are using a previous version, all help screens will still function as expected, but you may encounter references to features not available in a previous version(s). You should update your Joomla! version ASAP for these new features and security updates.
Joomla! 3.3 is the current STS version of the new Joomla! 3.x series. If you need a LTS version, Joomla! 2.5 is the current LTS version and will continue to be supported until 6 months after the release of Joomla! 3.5. Here is a selection that will help you get started.
For more information see the Joomla 3.3 category page.