Many (awesome) changes http://blog.jquery.com/2010/01/14/jquery-14-released/.

View the release notes here: http://jquery14.com/day-01/jquery-14

Related posts:

  1. jQuery 1.4.2 Released
  2. jQuery 1.4 Alpha 1 Released
  3. jQuery 1.4a2 (Alpha 2) Released
  4. jQuery 1.3.1 Go For Launch
  5. jQuery 1.3 Beta Testing