Our application extracts and replaces text in PPT and PPTX files. I have not run into any problems with updating PPTX files, but when updating a PPT file I often end up with a file where the paragraph spacing has been reset to 96pt, even though my code hasn't touched that.
Just to test, I simply opened the PPT with Aspose.Slides and saved it to a different file name - even without touching the file at all, the paragraph spacing is damaged. I'm attaching a ZIP file with a copy of a PPT file that exhibits this problem (it's simply the PowerPoint 2013 tour saved to PPT).
Never mind, my code was supposed to be using Presentation or PresentationEx depending on whether the file was PPT or PPTX, but it ended up using PresentationEx all the time.
Which brings me to my next question: if PresentationEx can open PPT files, can we expect it to work better in future versions?
I like to share that Aspose.Slides at present support limited capability to process PPT presentations using PresentationEx. The right class for accessing the PPT is to use Presentation class. However, I like to share that we are working over the unification of Aspose.Slides API where by we will be having a single iPresentation class for both PPT and PPTX. The said API is expected to be rolled out during Q1 of 2014. With the unified API you will be able to convert PPT to PPTX and vice versa.
Please share, if I may help you further in this regard.