Originally Posted by
jrl767
also check back about 5 min after the upgrade windows open (6pm local time at 5, 3, and 1 day(s) prior to flight)
NO, the upgrade window opens at 5 pm ATL time, 6/4/2 days before the flight (for example, Tuesday for a Monday flight, etc.). Some upgrade also seem to happen in the middle of the night, perhaps around 2 am ATL time.
In the past, we would have advised the OP to set free seat alerts on EF but sadly DL has taken away that option.