Exchange Server 2016 CU readiness checks error

I have downloaded the latest cumulative update (CU14) for Exchange Server 2016 and while running the setup (elevated) I receive several errors in the readiness checks.  These include:

The mailbox server role isn’t installed on this computer

and various others about permissions.  I clicked the link provided to get help but the destination page is far from helpful:

Sorry, but we haven’t added content for this Exchange 2013 readiness check yet

Amazing!  Well, despite the lack of help from that link I tried various things to fix this.  To cut a long story short, I had to move the AD Schema Master role to a domain controller located in the same site as this Exchange server.  Once I had done that the checks completed without warning or error and I could install the upgrade.