The WordPress dev team just announced the hat the next version, WordPress 3.2, will be released "very soon".
However, in a tweet WordPress has announced that the latest stable version of WordPress, 3.1, which was first released on 23 February 2011 has in less than 5 months, been downloaded over 15 million times.
Joomla just recently announced that its software has been downloaded 23 million times (note that this is the total number, not for any specific versions of the software solution).
With WordPress 3.2, Automattic will finally be dropping support for Internet Explorer 6.
Related: Automattic Hits 300 Million Unique Visitors, Roughly $10M In Revenue