At this time, we can go to the next topic's upgrade tests and validations for the PDC and execute all the checks that have been described until this phase of the procedure. The main services for our Active Directory Network must be fully functional (for example, users, groups, and machines). In case we found any issues that we can fix, rollback before going to the other servers (for example, file/print servers).
After we have confirmed that the right services are working up to this point and as our services are decoupled sufficiently, we have two options for each Domain Member Server at this point:
Move forward and upgrade them both as and when our maintenance window permits
Perform just a quick reconfiguration on the Samba 3 Servers (for example, join it to the Active Directory Domain), and continue their upgrade at another opportunity