It seems that the latest version of Server app (5.4) requires High Sierra (macOS 10.13) or later according to App Store. Up until now, we have been able to download updates for Sierra and El Capitan on Server app running on an El Capitan host with default settings. Even though the button says "Update" in the Server app description page on the host machine, it doesn't actually list it as an update in the App Store "Updates" tab.
Just wondering if we can fake it out by editing the conf files in Server app 5.2 (El Cap), and have it download High Sierra, Sierra, and older updates. We don't really have a machine available that can run High Sierra just for SWUS.
We have tried using NetBoot/SUS 4.1.0 on Linux for El Capitan/Sierra updates, but it was not reliable. However, it's been fine for netbooting Sierra.
Are High Sierra clients able to get updates from a macOS SUS server (assuming the server is running High Sierran Server 5.4 etc)?
I was under the impression that Macs running High Sierra or later would no longer be able communicate with "old-school" SUS servers.
I just read the online documentation, and it just says that it "supports catalogs for OS X 10.6 and later clients." So, I guess everything is still as it has been.
Roll your own reposado server either vm or bare-metal and be done. No issues with updates since 10.8, and currently have 10.13 updates including the files if you get the "stub" version of the High Sierra installer