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.