This update is recommended for all Safari users and includes improvements to stability, compatibility and security including:
- Stability improvements for webpages that use the HTML 5 video tag
- Fixes an issue that prevented some users from logging into iWork.com
- Fixes an issue that could cause web content to be displayed in greyscale instead of color
For detailed information on the security content of this update, please visit this site: http://support.apple.com/kb/HT1222.