I checked the OT homepage last week for the possibility to upgrade ARN-MAN (SK 2549) in early September. Nothing came up.

Called OT and they checked availability and the reason for no-availability was ”All upgrade request on your flight is taken, that why it does not show in your browser”. I asked about at what point this occur but he did not answer.

My question is how many requests can be done until this level is reached? At his point how many M pax has signed up for an upgrade on SK 2549 on my day of travel?