Since SetupOS is used as a streamlining function for hypervisor and virtual machine installation by node providers, i suppose it is not as critical to have SetupOS version mismatch.
However since you can have a many-to-many between HostOS & GuestOS and presumably newer versions of HostOS may have better security & other guarantees at the hypervisor level, i have an indirect question.
Is there impact analysis done with installing a newer GuestOS on a older HostOS? The real intent of this question is that with which HostOS is the proposed GuestOS tested?