Originally Posted by
UncleDude
The auto upgrade function will be available only if there are sufficient seats for all passengers on the booking.
Auto upgrades are available 90 days before departure up to 72 hours before departure.
Auto-upgrades only work if the reward seats are made available. And even then, it's hit and miss whether it actually works. You're better off checking regularly. But... it's very rare to see > 1 F seat made available until about 1 hour before departure time (you can ask in the lounge for them to check).