I am going to use Aspose Slides(ver. 1.9.0) for generating presentation which includes a lot of business logic. So users may use both .ppt and .ppts files for uploading, and/or willing to download the custom generated presentations in .ppt or .pptx format.
a) Is there any common API approach for handling .ppt and .pptx files?
b) Any means I can convert a .ppt to .pptx file or .pptx to .ppt file?
There is no common APIs approach as yet; but it is in our plan to make APIs common later when pptx development is mature.
There is no way to convert ppt to pptx file and vice versa; and we don’t have any plan to support this feature in near future.