title: How to open PDF/A-1 documents with a PdfCopy/PdfStamper that has a PDFA-2 or PDF/A-3 Conformance Level
body: <p>I'm still trying to convert from PDF to PDF/A, from PDF/A-1 to PDF/A-2, from PDF/A-2 to PDF/A-3. As you can see, my aim is it to achieve a PDF/A-3 conformance file from an existing PDF file.</p>
  
  <p>The problem by converting PDF/A-1 to PDF/A-2b is that it doesn't work. I am trying to open a PDF/A-1 conformance pdf-file with PdfACopy that shall create a PDF/A-2 conformance file, but this error occurs. </p>
  
  <blockquote>
    <p>Different PDF/A versions.</p>
  </blockquote>
  
  <p>Here is a little extract from my code:</p>
  
  <pre><code> using (Document doc = new Document())
          {
              using (FileStream fs = new FileStream(destPdfA, FileMode.Create, FileAccess.ReadWrite))
              {
                  using (PdfReader reader = new PdfReader(pdfPath))
                  {
                      using (PdfACopy copy = new PdfACopy(doc, fs, PdfAConformanceLevel.PDF_A_2B))
                      {
                          copy.SetPdfVersion(PdfCopy.PDF_VERSION_1_7);
                          copy.SetTagged();
                          copy.CreateXmpMetadata();
                          doc.Open();
  
                          ICC_Profile icc = ICC_Profile.GetInstance(ICC);
                          copy.SetOutputIntents("Custom", "", "http://www.color.org", "sRGB IEC61966-2.1", icc);
  
                          copy.AddDocument(reader);
                          PdfStructureTreeRoot s = copy.StructureTreeRoot;
                          Boolean a = PdfStructTreeController.CheckTagged(reader);
                          doc.Close();
                      }
                  }
              }
          }
  </code></pre>
  
  <p>How can I create or convert those PDFs? Do I need to read the metadata from the original file, change the PDF/a version, read it again and then change it?</p>
  
  <p><strong>Please, tell me how to convert those files. I just want a PDF-A3 conformance file.</strong></p>