I am using Aspose.Pdf for .Net v11.1.0 (newest version) to generate PDF/A-2 conformant PDF documents. This works fine for PDF/A-2b, but I get one conformance error when I select PDF/A-2a as output format: The key Marked is required but missing.
Code in attached test program is identical to your sample [on this page](https://blog.aspose.com/2014/10/22/pdf-to-pdfa-2a-conversion-set-resultant-file-dimensions-create-link-to-already-attached-files-with-aspose.pdf-for-.net-9.7.0)
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I used this online validator: http://www.pdf-tools.com/pdf/validate-pdfa-online.aspx
When I compare the output file to a file that is indicated to be fully conformant, the difference seems very minor.
Conformant file:
<</MarkInfo<</Marked true>>
File created with Aspose.Pdf for .Net:
<</Lang(nl-NL)/MarkInfo true
As the difference is so very minor, I wonder if there is a workaround? We are required to produce fully conformant PDF files and PDF/A-2a is preferred over PDF/A-2b.