I've got here a case where the user prematurely upgraded to Mojave in violation to our policy. In addition, I do now see no more management options for the client device but statistics exist and are coming in. Is there any way I could remotely promote the old status again so that the device becomes fully manageable? Screenshot attached
Is your Jamf Pro server running 10.6? That's the first version that from what I've read supports Mojave so I'd imagine older versions of Jamf Pro won't work well with Mojave. Sounds like MDM is broken if management shows no commands but the binary is working if usage statistics are coming in. You could try re-enrolling the device if you can reach it remotely with whatever remote desktop tools you have or SSH if enabled.
Not sure what you want to do with the management commands though, since I imagine you'd want to re-image the machine back down to High Sierra or whatever OS you have deployed in your environment.
Sorry, I meant the Jamf Pro server version 10.6, not the underlying Mac OS X version.
If it's the case that they just tampered with enrollment then re-enrollment would work. Or since it sounds like the binary is still working, SSH to the machine and do a
sudo jamf mdm
That'll get you the management pieces back that don't require DEP enrollment.