April 19th in their update, they said later in the year not the summer. The HoW raid couldn't be ready for launch like planned. They let us know a month and a half ahead of time. They are releasing another raid, as promised, later in the year. Will it be the one they were working on earlier? Probably not, since as you pointed out TTK focuses on the Taken and not the fallen. Will we ever see that raid? Maybe, maybe not.