[ovirt-users] Why difference between upgrade paths 3.6 to 4.0.x between RHEV and oVirt?

Hello, in June 2016 oVirt 4.0.0 GA was released and I in-place upgraded from an existing 3.6.5 to it. In 4.0.0 release notes it was described as the method to use. I see that it still remains the same for 4.0.5: http://www.ovirt.org/release/4.0.5/ and also for upcoming 4.0.6 (RC5 at least) there is not yet anything special: http://www.ovirt.org/release/4.0.6/ Instead, if I go and read the RHEV 4.0 documentation I notice: https://access.redhat.com/documentation/en/red-hat-virtualization/4.0/pag... " Red Hat Virtualization Manager 4.0 is only supported on Red Hat Enterprise Linux 7. A clean installation of Red Hat Enterprise Linux 7 and Red Hat Virtualization Manager 4.0 is required, even if you are using the same physical machine used to run Red Hat Enterprise Virtualization Manager 3.6. The upgrade process involves restoring Red Hat Enterprise Virtualization Manager 3.6 backup files onto the Red Hat Virtualization Manager 4.0 machine. " Is there any particular technical reason for this substantial difference? Clearly they are not the same sw but it seems strange to me this discrepancy. Suppose I have a mix of oVirt and RHEV environments it could be simpler to have a common path, where possible. For example, can I also use the documented RHEV approach for oVirt? At what extent? Thanks Gianluca