"the idea is that a group of rogue Predators on their world is not happy that they've been bested not once but twice – and perhaps more – by humans. They send their champions, and the champions never come home. "This is not sitting well with a group that's particularly contentious and ambitious. So I think they conspire to produce a second Predator, the one you see in the movie, who's basically an assassin. He is bred using traits from other species that they have hunted to be the enforcer, the guy who just gets it done. He has a sort of under armour as it were, almost like a crustacean. He goes from one colour to another like a chameleon, so he's got these weird survival skills."
Technically not brand new info, but I'm interested by what this implies - it reads that Upgrade was specifically created/enhanced for a purpose, rather than just roiding himself out because he wants to be better. I'm also happy with the phrasing "a group of rogue predators," since it reinforces my strong preference that it's just one sect doing this rather than the species as a whole.