I'm probably older than you are and I have the same problem.
Rather than answering your question, I'm going to show you how to answer this and similar questions yourself.
Go to Safari. At the top, type "history of macOS" or something like that. You will immediately get back a list of links including a Wikipedia web page with exactly the information you need.
I know because I remember versions of macOS by name, but need to type the number in XCode when I say which versions of macOS my program supports. I must have gone to this Wikipedia page 30 times in the last year.
This hint works even better for LaTeX. Search engines know an amazing amount about TeX. Every so often someone asks me why a certain style file, say thesisUO.sty, no longer works. I don't know, but in Safari I type "thesisUO.sty and latex 2.18" and bang, there is a detailed bug report about thesisUO.sty and all the fixes.
> On Nov 30, 2018, at 8:17 AM, Vic Norton <[hidden email]> wrote:
>> On Nov 29, 2018, at 12:59 PM, Richard Koch <[hidden email]> wrote:
>> Ghostscript 9.26 was released on November 20, 2018. There is an install package for this distribution on my web site:
>> http://pages.uoregon.edu/koch/ >
> At this link we see
> Ghostscript 9.26 was released November 20, 2018. ... The package works
> on macOS Yosemite and above, ...
> My problem is that I am old; I can’t remember names. I am on macOS 10.12.6, which my iMac says is “Sierra”. Does “Yosemite” come before or after “Sierra”. If I knew the “Yosemite” system number, I would have no problem. I do understand the order of numbers.