Deep apologies on my slow response. I've had my head down trying to push out our updated appliances.

FWIW, I have just posted a response to a somewhat similar question. We haven't yet released our updated PostgreSQL appliance, so if you need to do this ASAP, then the "in place" upgrade method is the only available at this point. Our updated v16.0 PosgreSQL appliance should be available within the next few days.