https://loc.gov/preservation/digital/formats/fdd/fdd000532.shtml

PDF/A‑4f is a version of PDF/A designed for archival storage that:

• Ensures long‑term visual and structural preservation
• Is based on modern PDF 2.0
• Allows embedded files (attachments) that are also archival‑compliant 

NetStandard: Missing content due to empty glyph outlines in embedded TrueType font subsets.

Workaround 1

Fully embed the fonts in the result PDF document:

PdfFormatProvider pdfFormatProvider = new PdfFormatProvider();
pdfFormatProvider.ExportSettings.FontEmbeddingType = FontEmbeddingType.Full;

Workaround 2

Switch to a .NET Framework project environment and use the .NET Framework PdfProcessing packages.

Here is a sample structure of the signature: 

/Type /Sig
/SubFilter /adbe.x509.rsa_sha1
/Filter /Adobe.PPKMS

InvalidOperationException is thrown when exporting a PDF document with a set compliance that processes Type3 font glyphs.

Workaround: Before export, set compliance to None.

var provider = new PdfFormatProvider();
provider.ExportSettings.ComplianceLevel = PdfComplianceLevel.None;

Endless loop on PDF export when an empty string is assigned to text fields with no source /V and auto-sized default appearance (/DA with 0 Tf).

Workaround: Instead of an empty string (""), set the value to null. Or don't set it at all and leave it unmodified.

Wrapped table cell text is incorrectly split by hyphens ("-").

This is a regression introduced in version 2026.3.826. Use an older version to avoid this issue.

From R1 2017 all annotations (including sound and video) are supported for import-export scenarios by using PdfStreamWriter class. 

These feedback item will be opened as we may add API for generating and inserting new sound annotations from scratch in the file.

When a source RadFixedDocument is merged to a target RadFixedDocument, the content of the source document is cleared.