Originally Posted by jdrtravel

I don't think this is at all clear. In my experience, Delta baggage policies are related to the cabin of travel, not the fare. I say this because passengers who have been upgraded retain their underlying fare class for all other purposes (mileage earning, ticket changes, waitlist priority, etc) but they are able to utilize first class baggage allowances. I understand the OP's confusion and I don't think we will have an answer until we get some reports from pax.