The following instructions are from the readme coming with driver 4.08:
Note: A previously installed kernel extension driver, like 3.2x, does not need to be uninstalled. It will be overwritten automatically. After that you could set the system security back to normal, unless any other existing kernel extensions still need reduced security.
To go back to 3.2x: easiest method is to drag the Fireface USB Settings app found in the folder Applications to the trash can - only use the Finder for this action. With DriverKit this Settings dialog is a complete package, upon removal all driver files belonging to it will also be removed automatically. You will be asked for permission for the removal of the extensions (yes). If done simply reinstall the former 3.2x.
As an alternative, in case the above method unexpectedly does not work, RME also made a version of the 3.27 driver available that should reliably remove the DriverKit extension during its installation. Download here:
https://www.rme-audio.de/downloads/driv … ac_327.zip
UCX - FF 400 - Babyface pro - Digiface USB - ADI-2 (original)
Mac mini M1 - Macbook pro - iPad Air2