Sorry, I should have read this thread from the start.
Canada is typically supported from day 1, and does not require a DRT upgrade.
However, you have a -US AP model, a DRT upgrade would not help anyway.
-US models are intended to be sold and deployed in the US and US territories only. They do not allow changing the country code to anything that could potentially FCC rules.
For Canada, you need a -RW model.
Confused how you would end up with a -US model in CA..