Why isn't the "Update iOS" feature working?

For iOS 10.3 and later and tvOS 12.0 and later, all supervised devices are eligible for software update management. Apple requires that the following is true for remote iOS updates to work:

  1. Device has detected that an iOS update is available for it in the App Store.
  2. Device has sufficient battery life available (at least 50%), or is plugged in to a power source.
  3. Device is connected to WiFi.
  4. Device does not have a passcode present.

Prior to iOS 10.3, the "Update iOS" feature only works for devices that were also enrolled in MDM via the Apple Device Enrollment Program (DEP). This feature is not available for tvOS versions earlier than 12.0.

You can check the eligibility of a device by navigating to device details. If an "Update iOS" option appears next to the current OS version, the device can be updated.