As others have mentioned, it appeared that Freeport was being discontined as of the middle of August this year, but then the contract was renewed and suddenly the Freeport stop was added to many itineraries already purchased.
I, too, had noticed that the Freeport dates are only listed until next Spring... but it's possible that the contract will again be renewed and that subsequent cruises will be converted to Freeport cruises.
My advice... if you <b><i>want</i></b> to go to Freeport... count on the calendar on alternating weeks from the last cruise that's marked as a Freeport cruise. Those are the cruises that are likely to be converted to Freeport cruises.
If you <b><i>don't</i></b> want to go to Freeport... count the alternate alternating weeks from the last Freeport cruise. Those are the cruises that are likely to remain non-Freeport cruises even if the Freeport contract is renewed.