Sitecore releases 6.4.1 Update-5 (rev. 111003)
Sitecore 6.4.1 Update-5 is a regular maintenance update with addresses a number of issues and also contains several improvements.
The main highlight in this update is that it introduces support for running the Sitecore user interfaces in Internet Explorer 9.
There are still a couple of known issues when running IE9 (see the IE9 known issue on SDN for details).
The main issue is that to use the Page Editor, Preview or Sitecore Debugger in IE9, you must enabled Compatibility View mode in IE.
Everything is already available on SDN, including: