Apple used to have a fantastic application called OSX Server (now called MacOS Server) which allowed you to run a full server from any OSX computer. A server can allow you share files, run your own email or web server, remotely connect in to your office etc. OSX server was particularly powerful running on a Mac Mini. With OSX Mojave 10.14 Apple killed off OSX server, but it is still possible to download an older version from Apple that still works. You need need to purchase OSX server on a newer Mac running Catalina, then go to an older Mac signed in using the same Apple ID and grab the older version of Server from the Purchase history.
You will need access to two Macs to do this.
Firstly you will need a Mac running an older version of OS X. This is the Mac you will run OSX server on. I used El Capitan but any version prior to Mojave will work.
If you try to ‘purchase’ OSX server on this older OS it will say that MacOS Server is not compatible with the older OS. The only way to purchase Server is to be running Catalina. (Note, according to the comment below this now needs to be Big Sur, Updated Feb 2021). So you may need access to a mac running OSX Big Sur to make the actual OSX Server purchase.
Once you have purchased Server you can then download the older version of Server to your older OSX.
1. Purchase a new version of MacOS server on a Mac running Catalina.
On the Catalina OS X computer, login to the App Store and purchase a new version of OS X Server. You don’t need to download it. You can cancel as soon as it starts to download.
2. Download the older version of Server on the Mac running an older version of OS X.
Open up the App Store on whichever Mac you are attempting to install macOS Server on. (The Mac with the older OS). Make sure you are logged into the same iTunes account you used to purchase macOS Server. In the
Go to your ‘Purchase History’. This can be done by either going to the Finder/Menu bar and clicking “Store” then “View my Account” or by clicking on your account name in the bottom left corner of the App Store window.
Look for the macOS Server app in your Purchase History and click DOWNLOAD. Make sure to download straight from your purchase history. Clicking on the app and attempting to install from its product page will not work. MacOS Server will now appear and you can download an older version that works with your older OS.
You should now have a working version of OSX server that includes all the features like VPN, FTP, Mail server and everything else that Apple removed from the Mojave version of OSX server.
There are lots of good comments below – worth a read.
Related Apple Support links:
What’s changed with Server 5.7.1
How to get an older version of OSX: