Atlas ships are under 10,000 tons, so they are allowed to enter Venice through the Guidecca Canal and dock at either San Basilio or Marittima. Ships up to 25,000 tons (that meet certain other restrictions, which I think Atlas ships should do) can dock at either terminal. None of the news items I have seen were written by people who have a clue about small-ship cruising so they are useless on this. Only Atlas will know for sure.