The unified rules are no more, and two rule changes are to blame. Come January 1st, there will be two distinct versions of the "unified" rules being followed by different states. This follows a controversial "package voting" method used to pass all proposed changes at the 2016 association of boxing commissions conference.
The first rule change will reduce the number of situations in which a fighter is considered a “downed” fighter, which will likely lead to more kicks/knees to the head of fighters getting up from the floor. This rule change came about to try to solve the problem of fighters “gaming” the system and looking for fouls by touching the ground.