Consider the following scenario:
- You create some server-based rules in a mixed Microsoft Exchange Server 2007 and Microsoft Exchange Server 2010 Service Pack 1 (or a later service pack version) environment.
- You apply the server-based rules to a mailbox that resides on an Exchange Server 2007 Mailbox server.
- You move the mailbox to an Exchange Server 2010 Mailbox server, and then move the mailbox back to the Exchange Server 2007 Mailbox server.