Originally Posted by Crisu69

usually this is correct. At the airport you can only upgrade the leg starting from this airport. Next leg you have to ask at the next airport (Doha)

But member spec119 reported he upgraded some days ago BKK-LHR 2 legs with miles in BKK already (this is how i understand his report).

if f is really nearly empty your best chance is to ask for upgade in the lounge in doha because now QR show only Q2 miles availability from doh-mel, which mean no upgrade possible for now. But good chance they open availability at airport later.

good luck and report your experience.