Hello folks (Are you guys ready for MMS? I’m on my way!)
Now that we have the Exchange Server 2013 CU1 the Service Pack 2010 Service Pack 3 became even more important and when you are running a larger organization or the person responsible for the Active Directory (Schema) is not the same person that will upgrade Exchange Servers then you will have to upgrade the Schema manually before upgrading the first Exchange Server 2010 to Service Pack 3.
Another reason to prepare the Active Directory separately is when the Exchange Server that you are upgrading is in a different Active Directory site than your Domain Controller that has the Schema role.
First of all, extract the content of Exchange Server 2010 SP3 on a folder on the C: drive of any Domain Controller (or log on the Exchange Server) and run Setup.com /PrepareAD
Time to validate the process, let’s open ADSIEdit.msc and open the Schema partition and let’s look for Ms-Exch-Schema-Version-PT and ask Properties.
Then, let’s check on rangeUpper and the value should be 14734.
If you are interested in the rangeUpper values among Exchange Versions, this KB can help you out: http://support.microsoft.com/kb/556086 (There is no Exchange Server 2010 SP3 over there yet :()
If you want to check all changes since Exchange Server 2003 to Exchange Server 2010 you can download this document: http://www.microsoft.com/en-us/download/details.aspx?displaylang=en&id=5401