Click here to see what is it for.
Be aware for this Known issues:
After you apply this cumulative update, you may encounter an issue when you try to use SQL Server Agent. For more information about this issue, click the following article number to view the articles in the Microsoft Knowledge Base:
976761 (http://support.microsoft.com/kb/976761/ ) FIX: Error message when you perform a rolling upgrade in a SQL Server 2008 cluster : "18401, Login failed for user SQLTEST\AgentService. Reason: Server is in script upgrade mode. Only administrator can connect at this time.[SQLState 42000]"
976953 (http://support.microsoft.com/kb/976953/ ) FIX: The SQL Server 2008 agent does not automatically resume running after you upgrade to SQL Server 2008 CU7 or SQL Server 2008 Service Pack 1 CU3/CU4 in a stand-alone environment
Bye.
Ronen