Fortigate VM snapshot

hi to all

is it supported by Fortinet taking/restoring  snapshots of Fortigate vms on virtual environments (vmware/hyper-v)? i'm thinking about the following use cases:

vm backup/restore

firmware upgrade/rollback

if possible should i power off the vm prior to take the snaphot or may i operate with the vm powered on?

i haven't found anthing on documentation bout this topic

thank you

Alberto