MS Exchange 2010 - SBS 2003

Hi,

I would like to ask the following.

I got SBS 2003 as the Primary DC with Exchange 2003 (All Mailboxes moved to new Server) and a Server with Server 2008 R2 and Exchange 2010 SP2 also a DC on the network.

I would like to know is it possible to upgrade the Exchange 2010 Server to SP3 with the SBS 2003 and Exchange 2003 still on the same network?

Thanks