As seen through partner Delta Air Lines,
https://www.delta.com/content/www/en...-partners.html
Effective
WestJet Mileage Earn On/After Sep. 20, 2018:
Business: J, C, D
Premium Economy: W, O, R
and changes in Economy classes as well.
Interestingly, still no 100% MQM on Discount Economy, although that might change if/when the Joint Venture is approved and implemented (this took about a year with Korean Air).
And weirdly, they are using T, K, L for Discount Economy which is the same class for Air Canada and many Star Alliance partners (United, Lufthansa, etc.)