The City of Toronto has advised that there was a delay in receiving renewal notices and permit stickers from the manufacturer, so they are kindly going to provide a grace period (conditions apply…).

These articles spell out what is happening and what you should do if you are affected:

Parking permit holders get grace period after renewal notices go out late (cbc.ca)
Sticker snafu hits Toronto on-street parking system (metronews.ca)

Update December 2, 2016:
The Toronto Star is reporting that it was not the manufacturer who was responsible for the delay, but actually a city administrative problem.
News Clarification for Dec. 2 (thestar.com)