Going back through old posts. What KIND of upgrade did you get?

Was the boarding pass on the Prestige paper? If so, that should be real full upgrade with business service (things like champagne and course meal).

Because they will often do Op Up for Morning Calm members. You will get business seat but economy service. Your boarding pass will still be on the economy paper but have a business class seat number.

On the plane, they split the cabin and move real biz passengers up to the front section and the op up in the back. They did this to me ICN-MNL once. I had Delta Silver (ST Elite) status and my friends nothing. We all got the seat upgrade but economy food and no champagne haha. I surely tried though!