Thanks for the help. I need to download those March 27 updates and then install on the MAC mini.
Then that would be the link provided by jonuk76
. That page will have all incremental macOS updates, security updates, Apple apps updates (i.e. apps like Safari, iTunes, etc) and other Apple updates that will come typically by way of the Updates tab in the App Store. The key thing is that you will need to know which updates you need, find them and download them individually. So, you likely will first want to go to the App Store and see what updates are listed there and write them down (with the EXACT title) so that you can then do find them.
One thing to note is that this will NOT include updates to non-Apple apps that you have "bought" (i.e. whether free or cost actual money) through the App Store. To my knowledge, those have to be done through the Update tab in the App Store. So, there is no way that I know of to download those updates on another computer. For most, this is likely not a problem as most apps on the App Store are pretty small, but there are some that can get quite large.
My original post will more apply when Apple releases a new macOS major upgrade...aka 10.13 (or whatever California landmark they name it after). This assume, of course, that you want to update to it and/or that you can update to it (i.e. your Mac was not dropped from support of new macOS versions).