HiQPDF error "Cannot write the document to output file. Invalid Serial Number Version." when merging 2 pdf

Question

I'm using HiQPdf to merge 2 pdf in one file, following to the official help: https://www.hiqpdf.com/documentation/html/e5d2f1ee-dccb-4351-888e-e3f3c15a93a5.htm I get the "HiQPdf Evaluation". Which prove the code works. I added my serial number:

PdfDocument resultDocument = new PdfDocument();
resultDocument.SerialNumber = "AU***************-OA=="; // this line is not in the help
PdfDocument document1 = PdfDocument.FromFile("c:\\temp\\doc1.pdf);
resultDocument.AddDocument(document1);
PdfDocument document2 = PdfDocument.FromFile("c:\\temp\\doc2.pdf);
resultDocument.AddDocument(document2);
resultDocument.WriteToFile("c:\\temp\\MergePdf.pdf"); //getting an Exception here !

I get an exception on the resultDocument.WriteToFile : Cannot write the document to output file. Invalid Serial Number Version. If I remove the resultDocument.SerialNumber, the merged pdf is generated but with the "HiQPdf Evaluation" water mark.

I assert that my serial is correct since I succesfully use it to for HtmlToPdf conversion:

HtmlToPdf htmlToPdfConverter = new HtmlToPdf();
htmlToPdfConverter.SerialNumber = "AU***************-OA==";
PdfDocument resultDoc = null;
resultDoc = htmlToPdfConverter.ConvertHtmlToPdfDocument(html, "");

This code (with my serial) succesfully produces a PDF without the "HiQPdf Evaluation: water mark. And if I remove my serial, the "HiQPdf Evaluation: water mark appears.

Is there another place/way to use the serial? Is it possible that my Serial is correct for htmlToPdfConverter but not the PdfDocument merging?

Answer 1

I finally received a response from the support: my serial is valid for a PREVIOUS version of HiQPdf.

Be aware that in Nuget, the only version available is version 12. To downgrade you need to find a backup of your previous version of HiQPdf.dll and put it manually in you packages.

Below the response from the support:

HiQPdf Sales [email protected] Mon 18/04/2022 18:20

Hello,

Your serial number is for version 10 of the software. For version 12 you need a new serial number.

You can renew the old license with a 20% renewal discount to obtain a serial number for the latest version of the software in the page below: [link removed]

Best Regards,

Jacob