There are a number of changes to the rules for 2017-2019 rule change cycle.
Many of these changes simply clarify rules in order that they may be interpreted correctly and consistently with how the rules are currently applied.
Follows these links for more details
Please also note the following rule change from the ORA:
Starting this season in Ontario, any four minute fully served penalty that cannot be served during the remaining clock time of the game shall result in a one game suspension. This includes any such fully served penalty assessed after the end of the game.