In this article We’ll walk you through how to perform a transition / upgrade from Exchange 2000/2003 to Exchange Server 2007. A transition is the process in which you perform an upgrade to Exchange 2007, that is you move data from any legacy Exchange servers in your Exchange organization to new Exchange 2007 Servers, after which you decommission the legacy Exchange servers. A transition should not be confused with a migration, because unlike a transition a migration is the process in which you move data from a non-Exchange messaging system (such as GroupWise, Lotus Notes or SendMail) to an Exchange organization, or move data from a legacy Exchange organization in an existing Active Directory Forest to an Exchange organization in a new Active Directory Forest.

It’s important to note that unlike previous versions of Exchange, in-place upgrades from Exchange 2000 or 2003 to Exchange Server 2007 aren’t supported, because, among other reasons, Exchange 2007 is 64-bit and therefore requires the x64-bit version of Windows Server 2003.

Note:
Exchange Server 2007 also exists in a 32-bit version but this version is meant to be used for testing and evaluation purposes only, so unless we’re speaking management tasks, it’s only the 64-bit version of Exchange Server 2007 that’s supported in a production environment.

Although in-place upgrades to Exchange 2007 are unsupported, I can assure you that a transition from Exchange 2000 or 2003 to Exchange 2007 in the same Active Directory Forest is a straightforward process, as I’ll show you throughout this article series.

Prerequisites

Before you even start thinking about deploying Exchange 2007 Servers in your existing environment, there are several requirements that must be fulfilled first.

You must make sure that the Exchange organization is set to Native Mode (no pre-Exchange 2000 servers) as shown in Figure 1.1 below.

Figure 1.1: Exchange Organization set to Native Mode

Since any pre-Exchange 2000 servers that may exist in your Exchange organization must be decommissioned before you can switch to native mode, it means that any Exchange 5.5 Servers in your organization must be properly removed before you can perform this step. 'So does this mean that you cannot do a transition directly from Exchange 5.5 to Exchange 2007 in the same Active Directory Forest?' I hear some of you ask. Yes that is correct! Those, hopefully few, of you who still have an Exchange 5.5 organization who want to move to Exchange 2007 must first upgrade from Exchange 5.5 to 2000 or 2003 and then do the transition from Exchange 2000 or 2003 to Exchange 2007.

You must also make sure that any Exchange 2000 Servers in your Exchange organization run with Exchange 2000 Service Pack 3, and that any Exchange 2003 Servers have Service Pack 2 applied. In addition you should take note that if you plan to keep at least one Exchange 2000 or 2003 server in the Exchange organization, the following services are unsupported by Exchange Server 2007:

• Novell GroupWise connector (Exchange 2003 Service)
• Microsoft Mobile Information Server (Exchange 2000 Service)
• Instant Messaging service (Exchange 2000 Service)
• Exchange Chat Service (Exchange 2000 Service)
• Exchange 2000 Conferencing Server (Exchange 2000 Service)
• Key Management Service (Exchange 2000 Service)
• cc:Mail connector (Exchange 2000 Service)
• MS Mail connector (Exchange 2000 Service)
  

You must make sure that the Domain Controller that is the schema master in your Active Directory runs Windows Server 2003 with at least Service Pack 1 applied. This is also true for any Global Catalog servers in each Active Directory site in which you plan on deploying Exchange 2007. Actually I recommend you run Windows Server 2003 with at least Service Pack 1 applied on all Domain Controllers in the Active Directory Forest. This version supports Exchange 2007 service notifications, allows users to browse the address book in Microsoft Outlook Web Access and provides the ability to look up distribution list membership in a more efficient manner than in Windows 2000 Server.

Note:
If you have any non-English Domain Controllers in your Active Directory, you should also apply the hotfix mentioned in MS KB article 919166 to those servers, as you otherwise can experience issues accessing the address book via OWA 2007.

Finally Exchange 2007 requires that the Active Directory functional level is set to Windows Server 2000 or Windows Server 2003 as shown in Figure 1.2 below.

Figure 1.2: Active Directory Domain Functional Level

If you’re unsure whether your Active Directory environment is ready for deploying the first Exchange 2007 Server, I recommend you run the latest version of the Exchange Best Practices Analyzer (ExBPA) to see if there’s anything you need to resolve before you continue.

The latest version of ExBPA version 2.7, which you can download at www.exbpa.com, includes an Exchange 2007 Readiness Check option as shown in Figure 1.3.

Figure 1.3: Exchange 2007 Readiness Check Option in ExBPA

You may also have heard that you must suppress Link State updates on any Exchange 2000 or 2003 Servers when deploying an Exchange 2007 Server into a legacy Exchange organization. But this is only true if you’re planning on having more than one routing group connection established between Exchange 2000/2003 and Exchange 2007. For the purpose of this article series we’re deploying one Exchange 2007 Server into a legacy Exchange organization consisting of one Exchange 2003 Server, and therefore don’t need to suppress Link State updates. If you plan on establishing more than one routing group connector, see this link for instructions on how to suppress Link State updates.