Since R21–R23 are older versions (2019–2020), some newer Arnold features aren’t available. But one very useful addition in is:
It is not the fastest Arnold ever made (440 lacks GPU progressive rendering), but it is the most reliable Arnold for those specific C4D versions. For studios locked into legacy pipelines, is the end of the road—and it is a very good place to stop. arnold render 440 for cinema 4d r21 r22 r23 r updated