ColorMunki and Retina screens

I recently bought ColorMunki Display to calibrate the screens of my Macs. It worked well on my 2009 MacBook Pro, but not so well on my 2017 iMac. In some user reviews on Amazon there were complaints that ColorMunki is outdated and doesn’t properly assess modern Retina screens. I’d appreciate any information on this point.

Paul Brians
Bainbridge Island, WA