The inclusions of pistons in the freeworlder is to make up the sum total of v1.7, and will be released on Thursday. The update will also “probably” include “a couple of bug fixes.”
Added the developer: “The adventure update will take however long it takes, and will be released as 1.8. It might be a long wait, but it will be worth it!”
The adventure side of Minecraft is being designed to “flesh out” the free-form indie title. Looks as though you’re not going to be seeing anything on it for a while yet.