How to determine Exchange version number:

Microsoft Exchange 2003 as a different version number depending on the applied service pack and updates.

To determine Microsoft Exchange 2003 version number:

1. Connect to the server where Exchange is installed.
2. Run "Exchange System Manager".
3. In the left side pane, Expand menu "Servers".
4. Then right-click the server name and select "Properties".
5. The "server name properties" Window opens.
6. In the "General" tab, just under the server name, you can see the version number, in my case:
   "Version 6.5 (Build 7638.2: Service Pack 2)".