Hi Adeogun,
Thanks for contacting support.
Aspose.Pdf for .NET supports the feature to create PDF file in particular PDF version or you can also update the version of any existing PDF file. Please take a look over following code snippet.
[C#]
//
load source PDF file<o:p></o:p>
Document doc = new Document("input.pdf");
//
set PDF file output version as v1.3
doc.Convert(new MemoryStream(), PdfFormat.v_1_3, ConvertErrorAction.Delete);
//
save the resultant file
doc.Save("output.pdf");
Besides this, you can also remove / replace fonts in PDF document by following instructions specified over
In case you still face any issue, please share the resource files and code snippet which you are using so that we can test the scenario at our end. We are sorry for this inconvenience.