Correct, users should never downgrade a monitor firmware. You are on the latest offered firmware. On the Windows OS side I see firmware M2B104, 2/16/2022.On the macOS side I see firmware M2B102, 9/27/2021. We are seeing other issues with macOS DDPM 1.0.2.0017. Uninstall macOS DDPM 1.0.2.0017. For testing purposes, install the macOS DDM 1.6.0.0014 and retest.
Hi, I have a Dell U3821DW running with M2B104 firmware. Upon starting DDPM 1.0.2.0017, A00 it claims I have an outdated firmware and tells me to upgrade. The only firmware for macOS I can find is M2B102, which is older than the one I have on mine. I have not tried to downgrade, seems counter intuitive to me. Please help. Regards, Marek C. 
U3821DW, macOS DDPM claiming wrong firmware