The title of this message is a lie. There is no official development schedule, and there never will be.
Those of you who have been around for a while, know that BYOND development tends to be somewhat of an unplanned spur-of-the-moment type of thing. A lot of great ideas get bantered around here on the forums and we find ourselves helpless to avoid some of them, and helpless to tackle others, given time constraints.
However, we have committed ourselves for a couple weeks to focus on stability, documentation, the website, and generally anything that would tend to make users frustrated, irritated, and homicidal.
After that cleanup phase, we will also become a bit more careful about releasing (potentially) buggy patches of hastily composed new features. I'm gathering together a suite of testing code, which I will run on all new versions, comparing the output to a file. That will help track down any low-level problems in the compiler/virtual-machine. Contribute anything you think puts a particular aspect of the system to test. (Library writers are especially encouraged to do so, since your code may be used by a lot of other people.)
To test DS, we will need some volunteers to try out new versions before they are made available to the public. You'll get new features right away, and new bugs too! Hopefully that will ease the pain and suffering caused by such changes as my recent garbage collection spree.
As for the future, we wholly intend to continue pumping out new developments, including many frequently requested graphical enhancements. Things have gotten to a point where the labor force, such as it is, has become stretched to the limits, so one of our next tasks will be moving this project to a stage where we can get some more people involved. We're not quite there, so don't ask yet!