On June 13, 2012, WordPress Version 3.4, named after guitarist Grant Green, was released to the public. For more information on this enhancement and bug-fix release, read the WordPress Blog, and see the Changelog for 3.4.
This new version features enhanced Theme control that allows you to preview Themes before publishing them. By using Theme Customizer you can customize theme options before activating a new Theme. Theme Previewer allows you to customize Themes without changing the front-end design.