PowerShell and Mailbox Anchoring

What a pain. A new feature by Microsoft that was apparently intended to enhance the experience of the Exchange Admin has instead created a new challenge for those supporting and or migrating Exchange Servers. If you don’t know what this is, please review the EHLO blog post HERE.
Why Does This Matter?
For those still running versions that are either Exchange Server 2013 CU10 and less or Exchange Server 2016, this won’t affect you. However, once you upgrade, this will affect you immediately. The impact is that if you are running either a mixed environment of 2013 and 2010/2007 or if you are upgrading from 2007/2010 and you are adding your first 2013 server and your build is CU11, your PowerShell connection will connect to the lower version of Exchange if that is where your mailbox is located. In a migration scenario this will cause some initial confusion because new cmdlets won’t be available and you won’t be able to configure your new Exchange 2013 due to this.


Workarounds
(1) You can move your mailbox and/or the arbitration mailboxes to the latest Exchange version in the Environment (2013 or 2016).
(2) Or you can run the ‘exshell.psc1’ file which is located in the ‘Exchange Server\V15\Bin’ directory on the Exchange Server.
I would recommend method 1 before doing method 2. If you can wait before applying CU11, see the next section for a better solution.
The Fix
Microsoft has decided to pull back these changes in the next releases of Exchange 2013 in CU12 and for Exchange 2016 CU1, the change will thus revert the connection back to the original non-mailbox anchoring method. So if you are upgrading either install a lesser version or wait until these releases come out.