Alaska Airlines is joining the Oneworld Alliance on March 31, 2021, and is making changes to fare classes eligible for instant upgrades at the time of ticketing for Mileage Plan elite members.
Part of the change is due to the fare class shuffle that Alaska Airlines institutes on February 24, 2021, due to better aligning them with, I would assume, with American Airlines.
You can access Alaska Airlines Mileage Plan here.
Here’s the old upgrade chart:
Here’s the updated one:
Just after having a quick look. Fewer fare classes are eligible for first and premium class upgrades.
I am not familiar enough with Mileage Plan to say whether this is a negative, positive, or neutral change for elite members.
If you are a frequent Alaska Airlines flier and hold status with them, you should study the tables above and the new fare structure instituted from tomorrow.