Some Windows 10 systems (typically new machines) with the most recent Version 2004 of the operating system have HVCI (Hypervisor-protected Code Integrity) activated. The used German expression is ‚Kernisolation’.
Drivers from 18.104.22.168 onwards are furnished with HVCI compliant driver signage.
Older Drivers are not started by Windows and are typically reported with error Code 39 in the device Manager.
The reason for the major version change from 6.4.2.x to 8.0.0.x is the migration from the underlying PLX to the more recent Broadcom code.