MacOS 10.12.6 and Profiler OS 8.5.4

I stay on MacOS 10.12.6 for my supercharged Nehalem machine with upgraded CPU/GPU/RAM to support my Pro Tools HD rig. The latest RM download says supported OS is now 10.13.6+, so am I to take it that I won't be able to update RM on this machine anymore? I could move to my laptop for RM, but it is just convenient to keep it on my same machine as I do my recording with. I get a message box each time I start RM that says to RM needs to be updated and to check website for info, but seems like it works properly otherwise after just updating the Profiler OS to 8.5.4.

As it turns out, RM is not working on my system now. It loads, but it doesn't recognize the Profiler and can't load profiles into it. Also can't install latest RM SW on this disk, so looks like I will be forced to move this stuff to my laptop. The hardware on this old Nehalem machine won't allow me to update an further than 10.12.6.