Apple will officially remove support for legacy MDM-based software update management in all 27 operating systems.
Announced last year, legacy software update management no longer functions in all 27.0 operating systems.
Software update commands, queries, recommended cadence settings, and update restrictions such as deferrals and Background Security Improvements will no longer function using the MDM protocol.
Going forward, your MDM solution must use Declarative Device Management (DDM) to manage and enforce operating system updates. Now it is time to check with your MDM vendor and confirm they have implemented this. BlackBerry UEM has DDM implemented and automatically switches capable devices over from MDM. There is no manual action required from the administrator to make the switch.

Jamf now officially announced that they will retrofit DDM-based software updates even to on-premises-Installations (which would be totally cut off from that functionality otherwise)