The beta contains several new features:
* Support for H.264 video and HE-AAC audio codecs .
* Enhancements to full-screen mode to use hardware scaling for improved video performance and quality on systems running Windows 2000 and newer or Mac OS X 10.2 and newer.
* Faster rendering of vector graphics on multi-core CPUs.
* Higher quality and performance for downscaling large bitmaps (SWF 9 only).
* Support for caching common platform components, such as the Flex framework, to reduce average application sizes. This feature is enabled in the Flex 3 beta available on Adobe Labs.
* Support for full-screen mode on Linux.

Also included in this update:
* Recursive calling to and from JavaScript via the ExternalInterface API is now permitted (not available in Opera or Netscape).
* Runtime errors can now be thrown from JavaScript to ActionScript via the External Interface API.
* HTTP requests from the Flash Player ActiveX Control in some versions of Internet Explorer did not include the Accept-Language header. The ActiveX Control now always inserts this header.
* Support for Microsoft Active Accessibility (MSAA) in the Windows plug-in.