Wow! Good to know. I thought my flight next week was full up front.
On a different note, my next trip booked through our corporate travel agency (Concur) is showing the option to pay to move to first on one leg of the itinerary. I have yet to see one of my corporate flights be eligible for FCM (used to see it all the time when buying direct).
The one leg upgrade is also something new to me. I've received that type of offer in the app at check in, but never ahead of time.