Upgrading to Exchange 2007
The Upgrading to Exchange 2007 topic includes the scenarios in which you either transition or migrate to Exchange 2007 from a previous version of Exchange or from another non-Exchange messaging system, or coexist with different versions of Exchange as a single Exchange organization.
Transition
Transition is the scenario in which you upgrade an existing Exchange organization to Exchange 2007.
You cannot perform an in-place upgrade of an existing server running Exchange Server 2003 or Exchange 2000 Server to Exchange 2007. Instead, you must install a new Exchange 2007 server into the existing organization, and then move data to the new Exchange 2007 server. Because a transition includes the installation of one or more new Exchange 2007 servers, some procedures will be the same as for new installations. For detailed steps about how to transition to Exchange 2007, see the following topics:
Coexisting with Exchange Server 2003 and Exchange 2000 Server
Interoperability is the ability of a program or system to share data and resources or to communicate with different programs and systems. Exchange 2007 can interoperate with non-Exchange messaging systems. In some cases, Exchange shares directory information and mailbox information with the other programs and systems. For example, with Exchange 2003 and the Lotus Interoperability and Migration Tools connectors, you can send calendar information and free/busy data between Lotus Notes and Exchange.
Coexistence is the scenario in which multiple versions of Exchange are deployed as a single Exchange organization. These multiple versions of Exchange can communicate with each other and share data resources, recipient information, and configuration information. For example, computers running Exchange 2007 can coexist with computers running Exchange 2003 or Exchange 2000.
For more information, see Coexisting with Exchange Server 2003 and Exchange 2000 Server.
Migration
Migration is the scenario in which you upgrade to Exchange 2007 by migrating data from a non-Exchange messaging system to Exchange 2007 or from an existing Exchange organization to a completely new Exchange organization, without retaining any of the Exchange configuration data in the first organization. Because migration includes the installation of one or more new Exchange 2007 servers, some procedures will be the same as for new installations. For detailed steps about how to migrate to Exchange 2007 from Lotus Notes, see Migrating from Lotus Notes.