To determine which version of Microsoft Exchange Server you are running:
1. Start Exchange System Manager (Exchange Server 2000 and later) or Exchange Administrator (Exchange Server 5.5 and earlier).
2. Click the Servers object for the Administrative Group or Exchange Site to which the server belongs.
The Server Version column lists information for each server in the group.
Note For Exchange Server 2000, the version is 6.0; for Exchange Server 2003, the version is 6.5.