Today, Apple published https://support.apple.com/en-us/HT208312, which states:
As of April 21, 2022, Apple has discontinued macOS Server. Existing macOS Server customers can continue to download and use the app with macOS Monterey.https://support.apple.com/en-us/HT208312
As someone that cut my teeth with OSX Server on 10.3 (Panther), I’d like to say farewell old friend.
In addition, Apple have posted a document on choosing and MDM solution and as well have another document advising that:
Apple will discontinue Fleetsmith service on October 21, 2022https://support.apple.com/en-us/HT213238
As of April 21, 2022, Apple has discontinued new signups for Fleetsmith.
Anyways, farewell macOS Server!