I remember years ago when a Y, B, and M domestic fare would auto upgrade into F space pending.
With over 74% premium cabin purchased these days, comp upgrades are pre-pandemic.
I have posted in the previous threads when this was announced last week that it will encourage ‘buying up’ to comfort plus now, but it is unknown the FCM offers that DL revenue management will offer— as I suspect will be very aggressive now considering that MM status is the #3 tiebreaker.