Joomla 1.7.4 and 2.5 were release today. Joomla 1.7.4 includes fixes for two medium priority and two low priority security vulnerabilities. Joomla 2.5 is the version that would have been version 1.8 in the previous version numbering scheme. Joomla 2.5 includes the same security fixes as 1.7.4 and also includes new features such as improved search, automatic notification of software updates, support for the Microsoft SQL Server, and more.
Support for Joomla 1.7.x will end on Februarty 24, 2012.
More information is available in the release announcement for 1.7.4 and 2.5.
