Joomla 2.5.1 in now available and this is a security release. Joomla 1.7.5 has been released too, but you’d better switch to Joomla 2.5.1 because very soon Joomla 1.7 will end reach of life.
As for Joomla 2.5.1, a few security issues and many tracker issues have been fixed to make it more perfect than the previous version of Joomla. Also, thanks to detailed instructions, it is really easy to update your Joomla site to Joomla 2.5.1 now. However, it is very important to backup your site before the upgrade.
Although, Joomla 2.5.1 is a security release, it may happen so that there are still some issues to be fixed in it and you find any, be sure to report it on the Joomla! CMS Issue Tracker.
Those who are new to Joomla are also invited to test Joomla 2.5.1 and see what it’s like. Thousands of people enjoy Joomla already; perhaps it’s exactly what you also need for your website.