The NFL passed seven rule changes related to play-calling, special teams, penalties, and more. Here's the full list.
The March NFL owners' meetings bring votes on potential rule changes, and the latest adjustments have been released. The most notable change is the permanent banning of all chop blocks. The league has moved in this direction, but prior to today there were some exceptions on run plays. A chop block is what led to Ian Williams ankle injury back in 2013. I don't believe that is connected to his most recent ankle surgeries, but who really knows.
Additionally, the league has made the extra point on the 15-yard line a permanent thing.