2-Disc BD Release | October 25, 2016
From the Exoricst III wikipedia page - -
On October 25, 2016, Scream Factory will release a 2-disc Collector's Edition of the film including the supposedly lost footage.[23] The website states: "We know that the biggest question you might have is: Will there be a “Director’s Cut” of the film? The answer is yes—but with some caveats. We are working on putting together a version that will be close to Blatty’s original script using a mixture of various film and video tape sources that we have been provided with. This is still a work in progress and we will update you with more details at the time we announce the full list of bonus materials."