Well, that is a surprise.
Anyway, it shows that v4 support isn't as poor as some would have it. I used EasyPix on one of my two systems for quite some time, and never had any problems. Indeed it remains one of my favorite calibrators, for its simple efficiency in spite of the obvious limitations.
But then I've always enabled v4 support in Firefox. Once you're down there in the basement flipping switches, it sits right next to the color management mode switch.