Delete Offline Address Book created with newer version of Exchange

A few weeks ago, I upgraded to Exchange 2013 from 2007. Shortly thereafter, we found that some of our applications were not compatible and decided to move to Exchange 2010 instead.

The migration to 2010 went smoothly, and all mailboxes were moved over to the new Ex2010 server without incident.

Now, however, I am attempting to uninstall Ex2007 and am encountering errors due to an existing Offline Address Book. The OAB in question was created by Exchange 2012 ("Default Offline Address Book (Ex2012)") and is still set as the default, even though Ex2013 has already been uninstalled.

I have created a new OAB, but am unable to set it as the default. I receive the error "The propery 'IsDefault' is on a read-only object and can't be modified". I receive the same error whether I attempt to remove the OAB via the Console or Shell.

When I attempt to delete that OAB, I receive the error "Default Offline Address Book (Ex2012) was created by a newer version of Exchange. Exchange version 15.0.0.0 or later is necessary to manage this object."

I tried installing Ex2013 Management Tools on another machine and using that console to remove the OAB, but receive the same error.

Is there any way I can force remove this OAB and/or set the newly created OAB as the default?

Any suggestions would be greatly appreciated.