Legal tender status to be removed in 2021
Canada will force people to redeem $500 and $1000 billions along with some smaller, older notes before January 1, 2021.
The move has been in the works for awhile but the end-date was unknown.
The Bank of Canada stopped printing the bills in 2000 at the urging of police. The high value notes made it much easier to facilitate high-value drug deals along with money laundering.
However since the halt, the bills have remained in circulation as they are passed back-and-forth within organized crime.
After 2021 the notes will not be worthless but they will only be redeemed at the central bank, which is a step that criminals and money launderers undoubtedly won't be fond of. The BOC estimates their are about $1.1B of the soon-to-die notes in circulation.
High-value banknotes have been the crosshairs of police for years. In Europe, 500-euro notes are known as "Bin Ladens" because of their use in illicit activity. The ECB discontinued producing the notes at the end of 2018 but there are still 255B euros worth in circulation and they remain legal tender (although the ECB has the power to remove that designation).
For reference, here is what $1 million USD looks like in $100 bills, which are the highest US denomination (this is from my personal stack, obviously). It's a manageable size for a large carry-on suitcase but if you're doing a deal for $5m or $10m, you're going to need some help and attract some attention.
In any case, I think money launderers and criminals have shifted at least some of the money into cryptocurrencies.