Universal Edition, UE 33137
Copyright 1921 by Universal Edition A.G., Wien.
Revised edition Copyright 2006 by Universal Edition A.G., Wien.
According to the foreword, this edition is based on an autograph score, possibly never copied to performance parts (guess: never performed). Also, however, the changes from the earlier edition are described and seem slight. (only a stage direction, a tempo marking moved, several cuts.)