Apple’s macOS Server 5.6 prepares for significant changes coming later in 2018 by hiding the following services from new installations: Calendar, Contacts, DHCP, DNS, Mail, Messages, NetInstall, VPN, Websites, and Wiki. Those services remain accessible to those already using them but will be removed from macOS Server in the next major release (see “Apple to Deprecate Many macOS Server Services,” 26 January 2018). Apple has provided a migration guide for moving to open-source alternatives.
The Profile Manager in macOS Server 5.6 supports new restrictions, payloads, and commands. In both macOS 10.13.4 High Sierra and iOS 11.3, you can configure a delay for user notification of software updates and enable or disable Bluetooth.
In High Sierra, you can also configure access to accessibility APIs for testing apps, permissions for kernel extensions (kexts), and Content Caching.
In iOS 11.3, you can require Face ID authentication before AutoFill, restrict remote connections from whitelisted devices, and require teacher consent to leave a teacher-created Classroom class.
For tvOS 11.3, you can configure Movie ratings, TV ratings, app ratings, and explicit content, and you can skip the ”Where is this Apple TV?” pane in Setup for devices in the Device Enrollment Program. ($19.99 new, free update, 194 MB, release notes, 10.13.3+)