This is an old CMS 6.0.0 update.

This is a product Update. Sitecore recommends upgrading to this release when the fixes included in this release meets specific needs of your organization. If this release does not include specific fixes that your organization requires, you may benefit by waiting until Sitecore releases a Service Pack for this series before upgrading. This is especially true in production environments. To learn more about Sitecore’s versioning system, see the Sitecore Versioning Policy page.

This update requires the following files:  

• Download Sitecore CMS 6.0.0 Update rev.090120 (Update-9) package (Sitecore CMS 6 package, 2.92 Mb)

To install the update on the existing Sitecore CMS 6.0.0 installation, follow the instructions below: 

1. Backup the site. 
2. Install the update package using the Installation Wizard available via the Sitecore desktop link Sitecore » Development Tools » Installation Wizard. Choose "Overwrite" every time when prompted.
3. If you are upgrading from version earlier than Sitecore 6.0.0 Update rev. 081222, remove the rest.html file from the /webroot/sitecore/ folder.
4. Update the web.config file. See the web.config changes page for details.
5. Clear your browser's cache. For instance, in Internet Explorer this is done via the menu Tools » Internet Options » Browsing History » Delete » Delete Temporary Internet Files.