During a search I found this nice kb article which explains how you can see which schema version you are using for Exchange and AD.

To find out which version you are using you will need to use a tool such as adsiedit. Below the full path where you can find the information plus a short overview which explains which versionnumber belongs to which Exchange version:



Check the value filled in at the following parameter rangeupper

4397 -> Exchange Server 2000 RTM

4406 -> Exchange Server 2000 with Service Pack 3

6870 -> Exchange Server 2003 RTM

6936  -> Exchange Server 2003 with Service Pack 2

10628 -> Exchange Server 2007

11116 -> Exchange 2007 with Service Pack 1

For more information have a look at the site below

How to find the current Schema Version


Johan Veldhuis