Close on the heels of Exchange 2010 SP 1 beta, Microsoft has just released Exchange 2007 SP 3. You can download the service pack from the download center. Exchange 2007 SP3 adds compatiblity for Windows Server 2008 R2 to Exchange 2007. With SP3, you can also install Exchange 2007 administration tools on Windows 7 clients.
Exchange 2007 SP3 includes some Active Directory schema modifications. These are listed in Active Directory Schema Changes (SP3) in Exchange 2007 documentation. Before you install SP3, you will need to update the schema and prepare the domain. More details in Exchange 2007 SP3 Release Notes.
Although Exchange 2007 SP3 supports Windows Server 2008 R2, you can’t upgrade the OS on an existing Exchange 2007 server before or after you apply SP3 to it.
More in Ask and you shall receive – Exchange 2007 SP3 w/support for Windows Server 2008 R2 Now Available on the Exchange team blog.