Brandon just announced that his work for Skyward 3
is now complete! Working title is still "Nowhere", but this is probably going to change before book is going to be released. Release date is on November, but exact day is still TBA.
On the last weekly update Brandon told that prewriting process for The Lost Metal is progressing fast (about 40% done) and should be done on next week. Prewriting doesn't mean that book is even close done, but frames how the storyline goes from beginning to the end should be done then :) So Brandon has got a clear picture how he is going to end the Mistborn series.