macOS Server 5.4
Apple has released macOS Server 5.4 with support for APFS volumes and new restrictions, payloads, and management commands for Profile Manager. The update now hides Open Directory and Software Update Service by default; integrates Caching Server, Time Machine Server, and File Sharing advanced options into macOS; and enables you to migrate Server data from a volume with OS X 10.10.5 Yosemite and Server 5.0.15 or later. Changes to Profile Manager include new supervised-only Classroom restrictions in iOS 11 to allow managed class behavior for unmanaged classes on supervised devices, new payloads in macOS (Extensions, Smart Card, and System Migration),
and a new AirPlay Incoming Security payload for tvOS.
Note that you’ll need to install macOS Server 5.4 manually because updates aren’t automatically installed (even if you’ve selected other apps to update automatically from the Mac App Store). macOS Server 5.4 requires macOS 10.13 High Sierra. ($19.99 new, free update, 194 MB, release notes and security content, 10.13+)
Apple stopped making real servers 10 yeas ago. So now, as they update their antique server software, they are requiring you to use High Sierra, which not only runs on newer hardware, is not even battle tested for real business. Apple: my server is nearly 7 years old, and will not run High Sierra, thanks to YOUR restrictions. WTF?
Frankly, unless you're using Profile Manager and need the new features or believe that APFS will help in some real way, I can't see much reason to upgrade Server soon.
You can try a Patcher which works for our xServe 3.1 dosdude1.com/sierrapatch.html
Is Time Machine server gone in the new server update???? I can't find any settings for, quota limits, or any management settings. Looked under sharing in system preferences??? bummer if those are gone???
The quota limit is available under the Advanced Options when right-clicking a shared folder in the Sharing pref pane. According to https://support.apple.com/en-us/HT207828#server
"You can configure a shared folder to be a Time Machine backup destination for Macs over the network in System Preferences > [Sharing >] File Sharing by Control Clicking the folder."