Long ago when I purchased the John Piper Sermon Manuscript Library I did so with the expectation that I would be receiving regular additions. The description then and now at http://www.logos.com/product/8601/the-john-piper-sermon-manuscript-library includes the advertisement, "Free regular updates of future John Piper sermon manuscripts".
It is now currently labeled 1980-2009. At the time of publication this was not the case (as it was published before 2009). There wasn't any advertisement then that the regular updates would cease in 2009. I hope that this isn't the plan.
Who is responsible for these updates, DesiringGod or Logos or somebody else?