A new Function was also added with this release. The function is “unregister_nav_menu()” and has been added so that child themes can unregister the existing navigation menu and add their own menus. One more change you will find that Twenty Ten theme has been updated to 1.0.1 version with this new release. Find more on what has changed in it from WeblogToolsCollection.
Download your copy of 3.0.1 or hit the upgrade button from the dashboard.