vic: ifr: mandatory. as always.
vfr: optional. as always.
in canada all flights over 25 nautical miles must be on a flight plan or a flight itinerary.
a flight plan is a document of safety, not of enforcement. if you're overdue at your destination, somebody will notice and people will start looking for you.
In most areas rules did not change and flight plans are not required.
A special zone was set up around Washington DC where you are required to be on a flight plan with a preassigned transponder code before entering.
Flight plans are still optional for VFR (Visual Flight Rules) flight. They have ALWAYS been required for flight under instrument rules.
Yes, they are still optional for VFR aircraft. The rules have barely changed in that regard except for border-crossing flights. .
Still not always required. Having to file a plan wouldn't stop anybody from ding bad things and the FAA knows it.