How to update Mac mini from High Sierra to macOS 10.14 or 10.15?

H AND J (Author)

Perhaps the paths listed to 'specific installer links' within

this article, may still work to get older versions of macOS.

How to download and install macOS - Apple Support

//support.apple.com/en-us/102662

Those I'd be interested, show exact archive file D/L URLs.

You should use Safari macOS Browsers, even if outdated.

And these macappstores files will only work in Supported

Mac version 'supported hardware' vintage build versions.

These in page URLs only directly open into macappstores then choose their own paths only:

• Catalina 10.15 <macappstores://apps.apple.com/app/macos-catalina/id1466841314?mt=12>
• Mojave 10.14 <macappstores://apps.apple.com/app/macos-mojave/id1398502828?mt=12>

Use the App Store

"To download macOS from the App Store, you must download from a Mac that is

compatible with that macOS. ~IF your Mac isn't compatible, the App Store dims

the Get button, says that the macOS is not compatible with this device, - or says

that the requested version of macOS is not available."

My Late 2012 Mac Mini (server) shipped with two 1TB 5400RPM Hard Drives and

upgraded (build-version specific) Two 8GB (16GB) 1600MHz DDR3 RAM chips.

(OWC RAM) and CPU 2.3GHz dual-core intel i7 & Intel Graphics 4000 1536MB.

Presently runs two partitions per HDD; (4) approx 499GB each. One w/ Mavericks

10.9.5 original Server version, installed. Others include Mojave 10.14.x + High Sierra

10.13.6. (Also has 'downloaded non-installed' version of Catalina, on own partition.)

.KIT has Apple Cinema Display, 20-inch (1680 x 1050) & shows correct in graphics.

.And an iSight original web camera, (with box) that shows its age; a bit grainy!