TMOS upgradation on Viprion with two vCMP

What should be the upgrade flow is it first the Host and then the guests or reverse or it dosent matter.

i would prefer upgrading host first.

Is it possible to keep the Host and the guest on the different TMOS versions?

sol14088: vCMP host and supported guest version matrix

Is there a document that can be followed for the flow of upgrade?

i do not see the document. anyway, i think just backing up all the configuration and shutdown all the guests (i.e. configured state) before upgrading.