Nonexistent. EDIT: Was going based off title, chance for hyper skills is nonexistent. Chances for new bosses is much higher, an example being Scarlion/Targa, who have been discussed many times.
New bosses (Scarlion, Targa, Pink Bean), maybe. Anything more than that, I don't think the version we're on supports it. Hyper skills? Probability of it happening is non existence.