Microsoft Exchange 2003 Version

With the DST issue, I was okay until I needed to know the version of Exchange 2003 we are running. That is, have any service packs been applied? I see no way to display that information. Only Belarc Advisor tells me that it is Version 6.5 which doesn’t indicate upgrades or revisions. I suspect that my predecessors installed it out of the box in ’03 and done nothing since.