List of wordpress Version’s
It may help, for your doubt
Source : http://codex.wordpress.org/WordPress_Versions
| Version | Release Date |
| 0.7 | May 27, 2003 |
| 0.71 | June 9, 2003 |
| 0.711 | June 25, 2003 |
| 0.72 | October 11, 2003 |
| 1.0 | January 3, 2004 |
| 1.0.1 | January 25, 2004 |
| 1.0.2 | March 11, 2004 |
| 1.2 | May 22, 2004 |
| 1.2.1 | October 6, 2004 |
| 1.2.2 | December 15, 2004 |
| 1.5 | February 17, 2005 |
| 1.5.1 | May 9, 2005 |
| 1.5.1.2 | May 27, 2005 |
| 1.5.1.3 | June 29, 2005 |
| 1.5.2 | August 14, 2005 |
| 2.0 | December 26, 2005 |
| 2.0.1 | January 31, 2006 |
| 2.0.2 | March 10, 2006 |
| 2.0.3 | June 1, 2006 |
| 2.0.4 | July 29, 2006 |
| 2.0.5 | October 27, 2006 |
| 2.0.6 | January 5, 2007 |
| 2.0.7 | January 15, 2007 |
| 2.0.8 | February 8, 2007 |
| 2.0.9 | February 21, 2007 |
| 2.0.10 | April 3, 2007 |
| 2.0.11 | August 5, 2007 |
| 2.1 | January 22, 2007 |
| 2.1.1 | February 21, 2007 |
| 2.1.2 | March 2, 2007 |
| 2.1.3 | April 3, 2007 |
| 2.2 | May 16, 2007 |
| 2.2.1 | June 21, 2007 |
| 2.2.2 | August 5, 2007 |
| 2.2.3 | September 8, 2007 |
| 2.3 | September 24, 2007 |
| 2.3.1 | October 26, 2007 |
| 2.3.2 | December 29, 2007 |
| 2.3.3 | February 5, 2008 |
| 2.5 | March 29, 2008 |
| 2.5.1 | April 25, 2008 |
| 2.6 | July 15, 2008 |
| 2.6.1 | August 15, 2008 |
| 2.6.2 | September 8, 2008 |
| 2.6.3 | October 23, 2008 |
| 2.6.5 | November 25, 2008 |
| 2.7 | December 10, 2008 |
| 2.7.1 | February 10, 2009 |
| 2.8 | June 10, 2009 |
| 2.8.1 | July 9, 2009 |
| 2.8.2 | July 20, 2009 |
| 2.8.3 | August 3, 2009 |
| 2.8.4 | August 12, 2009 |
| 2.8.5 | October 20, 2009 |
| 2.8.6 | November 12, 2009 |
| 2.9 | December 18, 2009 |
| 2.9.1 | January 4, 2010 |
| 2.9.2 | February 15, 2010 |
| 3.0 | June 17, 2010 |
| 3.0.1 | July 29, 2010 |
| 3.0.2 | November 30, 2010 |
| 3.0.3 | December 8, 2010 |
| 3.0.4 | December 29, 2010 |
| 3.0.5 | February 7, 2011 |
| 3.0.6 | April 26, 2011 |
| 3.1 | February 23, 2011 |
| 3.1.1 | April 5, 2011 |
| 3.1.2 | April 26, 2011 |
| 3.1.3 | May 25, 2011 |
| 3.1.4 | June 29, 2011 |
| 3.2 | July 4, 2011 |
| 3.2.1 | July 12, 2011 |
| 3.3 | December 12, 2011 |
| 3.3.1 | January 3, 2012 |