First of all, a big thank you to Mark for granting everyone access to the HP Utility. After spending the better part of a week back in January 2019 trying to find the right utility/OSX combination, I gave up and moved on to a VMWare/Windows combo for my profiling.
I'm now happy to say that the utility works on a variety of Macs using Mark's installer.
The first computer I installed it on was an old 2008 MacBook Pro running El Capitan. The computer has never had the drivers or the utility installed so it seemed logical to start from a clean slate. I installed the last HP driver from Apple and Mark's installer and everything is working as it should.
The second computer I tried to install it on was an ancient 2006 iBook G4 running 10.4. No go, both installers from Mark's dropbox require 10.5
Finally, I tried a 2010 iMac running High Sierra. It already had the drivers and HP Utility 5.38 but the utility did not show the Color Measurement menu option. For the heck of it, I decided to try to install the utility from Mark's 'El Capitan' installer without uninstalling everything first. After a very long install, it finally completed. The Color Measurement menu is there, you can select "Print and measure. . .", as well as the other options and it will proceed to the select the number of patches window. Like the MacBook Pro, I didn't go beyond that but it seems to working. Interestingly, it must have installed "missing" components because the Utility still shows the version as 5.38 (Mark's is 5.33).
Also, the installer will not work on a 2020 iMac running Catalina (10.15.7). When you try to run the installer, it gives a security error about not being able to check for malicious software.
I have a few more Macs with different OSes I'll eventually test it on. I'll post the results if and when I do.