There is no way to upgrade an Exchange Server 2003 or
2007 server to Exchange Server 2010. The changes in the database
structure alone are enough to preclude such a possibility.
However, that does not mean that there is no upgrade path
for environments with legacy mailbox installations. The key to
transitioning to Exchange Server 2010 lies in the concept of
coexistence.
Exchange Server 2010
can be installed into an existing Exchange Server 2003/2007 messaging
system. When Exchange Server 2010 has been introduced into the legacy
environment, the organization is considered to be in a state of
coexistence.
Table 1 lists the supported coexistence scenarios with earlier versions of Exchange Server.
Table 1. Supported Coexistence Scenarios
| Exchange Server Version | Exchange Organization Coexistence |
|---|
| Exchange 2000 Server | Not Supported |
| Exchange Server 2003 | Supported |
| Exchange Server 2007 | Supported |
| Mixed Exchange Server 2003/2007 | Supported |
Before you can
deploy Exchange Server 2010 in a legacy environment, the organization
must be operating in native mode. If the organization is already running
Exchange Server 2007, it is already in native mode. For Exchange Server
2003, you can go to native mode using the Exchange System Manager by
performing the following steps:
1. | Start Exchange System Manager. Click Start, point to Programs, point to Microsoft Exchange, and then click System Manager.
|
2. | Right-click the organization and then click Properties.
|
3. | Click
the General tab, and then, under Change Operations Mode, click Change
Mode. Click Yes if you are sure that you want to permanently switch the
organization’s mode to native mode.
|
Additionally, all
Exchange 2007 servers in the existing environment must have Exchange
Server 2007 Service Pack 2 installed before Exchange 2010 can be
deployed. Attempts to deploy Exchange 2010 into an environment with even
one Exchange 2007 server that is pre-SP2 will fail.
Once Exchange 2010
mailbox servers have been installed into the legacy Exchange Server
organization, mailboxes can be moved from the old environment to the
new. Once Exchange 2010 Client Access and Hub Transport servers have
been deployed, email address
policies and Transport rules can be updated or recreated. Once all
functionality provided by the legacy servers has been replicated in the
new environment, the legacy boxes can be retired.
