While korcula sounds lovely its not Dubrovnik ,Trieste or Rovinj , one port change is bad enough but three out of four? If I was booked on this one i would be looking to cancel or re book, when people book cruises the itinerary is usually the first consideration and having suffered the same fate earlier this year we were given the option to cancel or take enhanced obc and some substitute ports , it suited us as the ports that were cancelled we had visited before and looked forward to the replacements we had not been to, THREE days before departure one of the substitute calls was cancelled and "a relaxing sea day" replaced it ,to go with the twenty two others , we wouldn't have gone ahead if we knew this was to happen but with virtually no notice the option to cancel had gone, the same thing appears to be happening to a number of booked shore excursions , so i can only confirm that in my opinion operational reasons is a smokescreen and the only people who suffer are the paying passengers😒