Recently I had a conversation with a well-placed executive at UA. He confirmed, as others have (including
ua1flyer), that for flights served by three-cabin aircraft where first is not sold, upgrades are day-of-departure and based on fare paid then check-in time. However, a new policy is being developed that will be status-based and not limited to day-of-departure; no further details are available but would be announced later in the summer.
As always, Our Mileage May Vary
