How managed updates work
In iOS 11.3 or later and tvOS 12.2 or later, an MDM administrator can delay when new iOS and tvOS updates appear on supervised devices.
If your organization uses managed updates, you'll see a message that your device is running the latest software update allowed by your administrator:
In tvOS, you'll see a message that your Apple TV is up to date.
When updates appear
Administrators can delay when new iOS and tvOS updates appear on supervised devices for up to 90 days. This helps your organization test critical apps and infrastructure with a new update before deploying it.
Administrators can also remotely install an iOS update on your device. If your device uses a passcode, you'll be asked to enter it before a remote update can be installed.