Will Dorico work on Mac OS 10.8.5?
No, I’m afraid not. Dorico will only install and run on Mac OS X 10.9 or later, and we recommend running either 10.11 El Capitan or 10.12 Sierra if possible.
So the system requirements in the Resources page at the site are merely recommendations? I was left under the impression that Dorico would only run on El Capitan or Sierra, to be honest.