According to the developers blog: "This is a big update because we've added a lot of new cleaning capabilitiies, supported software, and user interface improvements."

The changes, as per the developer, are asfollows:

Added Session Cleaning for Firefox and Google Chrome.
- Added support for Google Chrome Canary Build.
- Added support for SRWare Iron browser via Google Chrome rule.
- Added support to clean custom Chromium based browsers.
e.g. CustomLocation1=CHROME|C:ChromiumIronPortableProfileDefault
CustomLocation2=CHROME|C:ChromePlusChromePlusUserDataDefault
- Added application support for Adobe Photoshop CS5, Adobe Illustrator CS5,
Adobe ImageReady CS, Nero Burning ROM 10, Google Calendar Sync
and Google Talk.
- Improved application support for Adobe Photoshop CS3, Google Earth,
Adobe Flash Player.
- Added support to search Uninstall Tool items by Publisher.
- Improved Custom Files and Folders accuracy to avoid duplicate reporting.
- Improved Include/Exclude Options.
- Improved Startup Tool functionality.
- Improved Registry detection algorithm for Missing Shared Dlls.
- Improved exception handling when cleaning W7 jumplist.
- Updated URL references to use piriform.com.
- Minor GUI tweaks and usability improvements.

download: http://www.piriform.com/ccleaner/download