The way things are looking ACPU may not continue to function properly even with the one RGB path it supports if the OSes change the way they have indicated they will. There are reasons why ACPU is unsupported software.
That's one of the reasons the engineers yanked it (NCM) out of Photoshop and released ACPU because it would be easier to rev ACPU for pipeline changes than Photoshop's print pipeline. As far as I know, the engineer that wrote ACPU intends to update it when needed by OS changes. But we'll see if/when Apple or MSFT makes major changes.