A question that is raised from time to time on the Symantec Connect forums relates to SQL Compatibility Levels and whether or not they are important. SQL Compatibility is described by Microsoft as :
"Compatibility level provides only partial backward compatibility with earlier versions of SQL Server."
-- Reference: http://msdn.microsoft.com/en-us/library/bb510680.aspx
You can see the current SQL Compatibility Level by executing:
select name, compatibility_level from sys.databases
In the end you want this to match your SQL Server version, running at an older version can have undesirable effects on Enterprise Vault. The Enterprise Vault Compatibility Charts state:
"Note: Enterprise Vault supports SQL databases only at their default compatibility levels."
--- Reference: http://www.symantec.com/docs/TECH38537