I got the same notice for my debit card. I think that different people may have gotten slightly different deadlines, but in my notice it said that my card will stop earning points on July 12 (or any transaction that posts on or by July 15, as long as it is initiated by July 12), and that beyond that point I have until October 31 to redeem my Dream Reward Dollars and transfer them to a redemption card. So for me, any purchases made beyond July 12 are no longer eligible to earn any reward dollars, but I have until 10/31 to claim what I earned.
Also, after October 31 (for my card) there will be no more discounts at the Disney theme parks on food or merchandise, no more discounts on things like tickets (for the Halloween party) or any other perks of the card. Basically, they are cancelling the whole points/perks program for the debit cards only - and Chase is cancelling its rewards/points programs for all of its debit cards, not just the Disney Visa ones.
But as the PP's stated, it's only the debit that is affected. The Disney Chase Visa credit card will stay the same.