Now, Joomla! 3.3 is the current stable version, and is recommended to use for new sites.
(Joomla = all together)

  • Available! Joomla 2.5: March 2012 (LTS release)
  • Available! Version 3.0: September 2012
  • Available! Version 3.1: March 2013
  • Available! Version 3.2: September 2013
  • Available! Version 3.3: March 2014
  •                   Joomla 3.4: ==> 2015