Can I resave PDF documents using different versions of PDF
Using PDFNet you can modify PDF header and versioning information. For
example, to save a document using a different header string using
pdfdoc.GetSDFDoc().Save(...) instead of pdfdoc.Save(...). For example,
to save the file with 'PDF 1.3' in the header use the following code:
pdfdoc.GetSDFDoc().Save("my.pdf", 0, "%PDF-1.3");
Please keep in mind that, the main difference is that the saved
document will have a different header and versioning information.
PDFNet will also make sure that the Cos (i.e. low-level)
representation is fully compatible with the specified version of the
target PDF document. If the document contains high-level features that
are not available in the target version, the features will not be
discarded. In most cases Acrobat Reader ignores or gracefully handles
features that are not recognized.
You could also use PDFNet to process and edit PDF documents to make
sure that saved document fully conforms to the given PDF revision
(e.g. by recompressing JBIG2 and JPEG2000 streams or flattening
transparency etc.), however this should be done as a pre-processing
step before pdfdoc.Save().