Our Linux Admin tells us that the image he downloads is from REDHAT and not from POSTGRES and it allows only one version of Postgres to be installed at any given time.
Either this is true and you can’t do what you want below, or it’s false and you can.
But yeah, usually either you install two versions one the same machine at the same time e or you install one version on each of two machines at the same time. Both these tend to minimize downtime and risk. There is a bit of complexity to do either.
