I remember them saying in one of the April Update videos that they will be doing away with the Treasure Keys used in the Prison of Elders. However, they also said that classic Prison of Elders would go untouched. So I've just been wondering, which is it? Will there still be Treasure Keys needed for the old Prison of Elders?
I ran through Level 34 PoE with 5 treasure keys last night. It did not use a key to open the chest. Maybe it linked to TTK DLC as to whether or not treasure keys are needed. But I guess all 15 of these keys I held on to are just trash now.