The format supported by PowerPoint 2007/2010 in Aspose.Slides for Java are PPTX, PPSX and POTX. Secondly, i would recommend you to use PresentationEx.write() method instead of using PresentationEx.save() for saving presentations. You can simply save any presentation in above mentioned formats using PresentationEx.write() by using any of above mentioned formats. Moreover, I also like to elaborate that the above mentioned formats are used by both PowerPoint 2007 and 2010. PresentationEx has to be used to access these presentations.