From the FAQ:
Is Keyboard Maestro compatible with Yosemite?No, Keyboard Maestro 9 requires 10.11 or later.
Is Keyboard Maestro compatible with Sierra?Yes, Keyboard Maestro is fully compatible with Sierra. In fact, Keyboard Maestro versions going back as far as version 2.x still work fine on Yosemite.
If you read the answers forensically, you can figure out that maybe they refer to different versions of KBM, but that is buried and obscured by terms like "full compatible". The direct answers to the questions are "No" to Yosemite and "Yes" to Sierra. That is confusing.
In the Forum:
The very first item, pinned to the top, of the Questions and Suggestions category says
About the general category
This is the category to use for most questions, suggestions, feedback or the like.
Use this category if you want to know how to do something, or have a suggestion for how Keyboard Maestro could be made better, or feedback on any area of Keyboard Maestro
And yet, I can find no "General" category anywhere. I am left with the nagging question, "How do I make a post in the General category?". I presume that is where this particular post about the FAQ belongs, but without being able to find "General", I'm just going to have to cross my fingers and post it in the "Questions & Suggestions" and hope that someone more knowledgeable will move it to where it belongs. That's an uncomfortable user experience.