Upgrading from SEP 12.1.1 to SEP 12.1.4 - What SQL Server Compatibility Level to choose?

We are in the process of updating from SEP 12.1.1 to SEP 12.1.4. As a part of it, we have to upgrade SQL Server from 2005 to 2008. Once upgraded to SQL Server 2008, which Compatibility level should we choose or is recommended?

Thank you in advance.

Alex