Update Looks like it is dead Jim! 4/21/2022:
https://support.apple.com/en-us/HT208312
Looks like the writing is on the wall for Apple Server.
Dumping many services, and suggesting replacements.
https://support.apple.com/en-us/HT208312
As always, here is a cut and paste of some of the details in case it goes away.
Prepare for changes to macOS Server
Learn about changes coming to macOS Server in spring 2018
macOS Server is changing to focus more on management of computers, devices,
and storage on your network. As a result, some changes are coming in how Server works.
A number of services will be deprecated, and will be hidden on new installations of an
update to macOS Server coming in spring 2018. If you've already configured one of these
services, you'll still be able to use it in the spring 2018 macOS Server update.
These deprecated services will be removed in a future release of macOS Server,
so those depending on them should consider alternatives, including hosted services.
Deprecated services are listed below. Links to potential replacements are provided
underneath each deprecated service.
Calendar
Calendar and Contacts Server
DavMail
Radicale
Contacts
Calendar and Contacts Server
DavMail
Citadel
DHCP
Kea
Dnsmasq
FreeRADIUS
DNS
BIND
Unbound
KnotDNS
Mail
KerioConnect
dovecot/Postfix
Courier
Messages
ejabberd
Openfire
Prosody
NetInstall
NetSUS
BSDPy
VPN
OpenVPN
SoftEther VPN
Tcpcrypt
Websites
Apache HTTP Server
Nginx
Lighttpd
Wiki
MediaWiki
PmWiki
XWiki