I have had the same issues as others where the Riing Plus software fails to detect or control the the new fans. However, the weird thing is that I happen to load (by mistake I have to admit) the Premium RGB software during my testing and it finds and controls the fans fine. You don't get any of the cool functions of the Plus fans like individual led control, etc but you can do anything the RGB's do. I tried reinstalling the Plus after I got the other to work but the Plus software still shows 0 rpm and obviously doesn't detect the fans.
Short version - for me it's not a hardware issue since the wrong software can control the fans.