Upgrade from 8.5.2 to 8.7.1


We have 8.5.2 installed against Active Directory with WIndows 7 clients.

We are about to deploy Windows 10 clients in the same AD tree and wish to update to latest (8.7.1).

We don't want to disturb the existing clients or application definitions.

I read the documentation and ended up more confused - particularly when it talks about changing the Datastore Version to 7 during the upgrade, then setting it back to 6 at a later step.

Is there anyone who has done this or that can advise me what needs to be done ?