My husband and I received an upgrade on Century (from category 12 inside to category 5 outside) that we are very happy about. We had booked the cruise on a guarantee ($599pp including port charges and fees) and got lucky. I think the free upgrades are usually given to people who book a guarantee or run of the ship. I'm really not certain how the upgrades are done though. I just wanted to give you a little hope because we were very excited about our upgrade. Good luck!!!!