Originally Posted by ILS2

Definitely SK 903 on June 2nd. Only two seats that has not been pre-reserved in Economy, which usually means they will be oversold in M. That will lead to op-ups to Y+, which in turn means op-ups from Y+ to C. This has happened to me many times now, especially around holidays.

On SK 904 on June 7th, Business Class actually comes up as sold out(!), so little or no chance for an upgrade to C at the moment.