Originally Posted by
entropy
IIRC,
"Gate Upgrade" refers to an upgrade given after normal EUA but before the passenger has boarded
"Battlefield" refers to an upgrade cleared after the passenger has boarded, who subsequently has to battle their way upstream to get their new seat.
Oh, I see... I personally considered any upgrade within 2hrs prior to departure time as "Battlefield Upgrade", since Plat/Gold companions will join the "battle" at that time.
But if we separate "Gate Upgrade" from "Battlefield Upgrade", and the latter means only after boarding, I'll use that way from now on.