This version of iTunes resolves an issue where the equalizer may not work as expected and improves performance when switching views in large iTunes libraries. This update alos includes additional minor bug fixes.
The previous version of iTunes added support OS X Mavericks, Arabic, and Hebrew.
Note: If you are using OS X Mavericks, your book library can now be found in iBooks for Mac.
You can download the update by selecting Software Update from the Apple menu at the top left of the screen.