Just adding to the list - booked a KLM ticket with Z class available.
called 3 times - each time they said that new terms this month state that only 1 class upgrade is available on KLM as of this month.
Since when can they change terms and conditions in the middle of the year with no notice on their website? I know we are a small fraction of GUC usage but this was where the value was in GUC and now it’s gone.