PowerShell Quick Script: Finding the Exchange Schema Version

Every major Exchange release comes with updates to the Active Directory schema. In this case, "major release" means new major version (at RTM), every service pack, and (probably) every Cumulative Update with the new servicing model introduced for Exchange 2013.

Each update is unique to that particular release and, in general, they are cumulative. A notable exception to this was when Exchange Server 2007 SP3 had a higher schema version than that of Exchange Server 2010 RTM.

Over the lifetime of modern Exchange (since the integration to Active Directory with Exchange 2000), there have been a number of issues making it important to know the current schema version of Exchange. Most instructions on the web suggest using ADSIEdit to examine the relevant variable and value.

However, that is potentially risky (because ADSIEdit can be a dangerous tool) and can be a little confusing to use.

Here is a quick little PowerShell script to report on the proper value:

$root = [ADSI]"LDAP://RootDSE"
$name = "CN=ms-Exch-Schema-Version-Pt," + $root.schemaNamingContext
$value = [ADSI]( "LDAP://" + $name )
"Exchange Schema Version = $( $value.rangeUpper )"

The ms-Exch-Schema-Version-Pt attribute is never assigned to a class in the schema, it is used exclusively to identify the value of the Exchange Schema Version.

To anyone who has used ADSI in PowerShell or VBScript before, the little four-line script will appear very familiar. The PowerShell ADSI accelerator syntax allows for the corresponding PowerShell script to be shorter than the equivalent VBScript script.

In order for this script to work, it must be executed on a computer joined to an Active Directory domain. The execution context for the script (that is, the user account) requires no special privileges.

Oh, and if you prefer PowerShell one-liners, here is the same script as a one-liner for you:

"Exchange Schema Version = " + ([ADSI]("LDAP://CN=ms-Exch-Schema-Version-Pt," + ([ADSI]"LDAP://RootDSE").schemaNamingContext)).rangeUpper

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