Hi,
Thank you for using Syncfusion products.
Changing PDF version
In version 6.1.3.8, we have hardcoded the PDF version as 1.5 by default. We can change the version number for the PDF document with the help of the Version property of the FileStructure class.
Kindly use the below code to change the version number,
//Changing PDF version as 1.4
doc.FileStructure.CrossReferenceType = PdfCrossReferenceType.CrossReferenceTable;
doc.FileStructure.Version = PdfVersion.Version1_4;
Please do find the sample from the below specified location and let me know if this helps,
http://www.syncfusion.com/support/user/uploads/Pdf_Window_76711_7ee5e792.zipRegards,
Suba