Where can I get Os X server 5.4 for High Sierra

High Sierra running Server 5.4 seems to be the last server combination that acts as a server, but Apple's online instructions of how to update the server from previous versions (e.g., 5.2) has failed on two separate systems. Apple instructions (https://support.apple.com/en-us/HT20804) say to upgrade the OS first and then update the Server app from your 'Purchased' apps, but on two different systems that I have tried, the update never downloads, and the update page just hangs forever with a spinning wheel. If I then delete the installed server, and select 'Install' from the 'Purchased' apps page, then I get the non-server Server version of 5.6, which kills DHCP, DNS and File services. Anyone find a way to get the 5.4 version which still has server services?