In our case, we booked a Venice to Istanbul in October, 2024, on Vista. Venice, Hvar, and Dubrovnik have been replaced by Rome, Amalfi, and Catania. The reason given is the ship restriction size that Venice is imposing. It was not stated, but I'm guessing that too many people have complained about the alternative ports forced on cruise ships to use as "Venice," and the stiff competition by all lines vying for those alternate ports has become problematic. We are disappointed about Venice, a city we enjoy. However, we wouldn't have embarked in Venice, anyway, so the impact on our expectations wasn't an issue since we've been to Venice and Dubrovnik before and this cruise was chosen because of the itinerary in Greece and Turkey.