This is an article I first published a couple of years ago to check what schema version a customer was running when performing an Exchange upgrade. There have since been official articles published by Microsoft, but I prefer to keep my own blog post for easy access.
This article outlines how to find the Exchange schema and version in of your Exchange schemas. There is also a list of the schema versions per build type.
To find the attributes listed below use Adsiedit.msc. When you launch asdiedit.msc there are 3 containers listed.
- Domain: [Domain Controller FQDN]
- Configuration: [Domain Controller FQDN]
- Schema: [Domain Controller FQDN]