How do I make PDF compatible with 1.4 (Acrobat 5)? What is the current default serialization format for PDFNet?

Q: Has the default PDF version become 1.5 in recent pdftron/netsdk
versions? Particularly what we do is the following:

public static byte[] RepairPdf(Stream pdfStream) {

byte[] buffer;
try {
pdfStream.Position = 0;
using (var binaryReader = new BinaryReader(pdfStream)) {
var fileBuff =
using (var pdfDoc = new PDFDoc(fileBuff, fileBuff.Length)) {
buffer = new byte[1];
var bufferSize = 1;
pdfDoc.Save(ref buffer, ref bufferSize,
return buffer;

... and it seems like when providing a 1.4 one as input, they get
returned as 1.5/Acrobat6 now? Has anything changed in one of the
recent versions/5.5?

A: Yes, starting with v.5.5. PDFNet is by default saving 'Compressed
PDF' (compressed objects + compressed xref) which results in smaller
files (e.g. 9 mb vs 18 mb for ISO 32000 pdf !).

If you would like to make PDFs compatible with older viewers (e.g.
Acrobat 5) you can use e_compatible flag in the call to pdfdoc.Save().
For example:

pdffoc.Save("my.pdf", SDFDoc.SaveOptions.e_remove_unused |
SDFDoc.SaveOptions. e_compatible);