The update is right around the corner. The corner is located on a back street in Smolensk. The corner also happens to be on a building slated for demolition. The building upon which the corner is located is a used adult video store. At the moment, a secret nuclear bomber is on it's way to blow up Smolensk to show those darn commies who they are messing with. This inevitably leads to global thermonuclear war. London is one of the first cities to go. Chucklefish dies. Rest in peas, Starbound.
Well, they've actually got a ton done in the Nightly Builds. The reason they don't throw stable updates anymore is so they can work with their unstable version and don't have to bother making it balanced or anything till they release. Then its 8 months later and they have to fix bugs and balance everything quick. It might actually be within a week or 5. You can use them right now if you want to, just use the beta in the properties window on steam. A Beta version in a beta. Teehee.
No, the reason they have nightly builds is because those builds are unstable and have not been tested. To release stable builds, they need to make sure it won't create corrupted worlds / crash frequently / etc, and that slows down development. Having backlash from the community for releasing frequent stable builds also contributes to the reason why we haven't had a stable build in a while. That being said, the next stable build is probably around Christmas time (Steam sales).
