The Aurora Remote Control software (ARC), is a 32-bit application and macOS Catalina requires 64-bit applications only. The ARC is used for USB and FireWire connection methods, the thunderbolt and PCIe connection methods use the Lynx Mixer which WILL work in Catalina.
There are no plans to create new versions of ARC, as the Aurora 8/16 have been discontinued for many years. One possible workaround is to use a computer with an older OS to make changes to the unit, power cycle from the front panel power button to save this state, and then use it in Catalina. The audio performance in Catalina is fine, as the Lynx USB and FireWire solutions are class compliant and the OS provides the necessary drivers.