How to determine the version of AD schema or Exchange schema: http://support.microsoft.com/kb/556086/en-us

dsquery * cn=schema,cn=configuration,dc=domainname,dc=local -scope base -attr objectVersion

or

adsiedit.msc or ldp.exe:CN=Schema,CN=Configuration,DC=domain,DC=local   Then, review the current objectVersion attribute.

The table for AD schema:

Windows Server 2012 56
Windows 2008 R2 47
Windows 2008 44
Windows 2003 R2 31
Windows 2003 30
Windows 2000 13