Given the changes embodied in LEED v4 and the feedback from users I think that USGBC made a very wise decision. This will give users more time to assimilate the changes and prepare for the changeover while continuing to use LEED 2009. For those firms either already using LEED v4 or just starting to use LEED v4 this change will allow them to continue on that path. It will also give both USGBC and users more time to educate clients about LEED v4.