A manula update is available on Motorola ATRiX 4G user on the Motorola Update page you can download by visiting this link
Android 2.3 (Gingerbread), Version 4.5.91 Release Notes is available at this link.
Some of improvement are in this update
Enhancements to the picture Gallery allow you to aggregate all your photos, yourfriends’ photos and photo comments from social networking and photo sites like Facebook and Picasa in one place for easy viewingEnhancements so your Music player is now connected to a dashboard for music discovery. Plus, easy access to all your favorite artists, live, personalized recommendations for songs & videos and news and event updatesUpdated user interface with simpler home screen design, including shift to use of white backgrounds in menus, enabling better viewing experienceEnhancement that enables easy access to favorite apps at bottom of each screenEnhancement that helps you personalize and categorize favorite apps into groups so you can be more efficientEnhancement that provides access to social content in one place so you can find out what is happening around you. You can use Yelp reviews and Facebook check-ins to find out what others are recommendingYou can now install any app you’d like, including the Amazon App store