You need to explicitly set the correct MIME type when embedding the file into the PDF. This is especially important for standards like PDF/A-3 and Factur-X, which require strict metadata and MIME type declarations for embedded files.

The default value /application/octet-stream is too generic and not compliant for XML attachments.

 

Handle the import of documents with an invalid cross-reference stream offset.

Provide an API for externally signing the document hash.

When import-export a document with embedded font(s) and FontEmbeddingType.Subset set, the subset collection is not updated, and the originally imported font is exported unmodified.

System.ArgumentException: 'An item with the same key has already been added. Key: Telerik.Windows.Documents.Fixed.Model.InteractiveForms.RadioButtonField'

It is reproducible when you have at least 2 pages with RadioButtonFields. The import operation goes smoothly. However, merging or removing a page after import leads to the described error.

If the document contains an image that fails to be imported properly, an internal error occurs and the import process is interrupted leading to incomplete document with missing elements. 

From the Part 4: PAdES Long Term - PAdES-LTV Profile (ETSI TS 102 778-4) Specification: 

"Validation of an electronic signature requires data to validate the signature such as CA certificates, Certificate Revocation List (CRLs) or Certificate status information (OCSP) commonly provided by an online service (referred to in the present document as validation data). If the document is stored and the signatures are to be verifiable long after first created, in particular after the signing certificate has expired, the original validation data may no longer available or there may uncertainty as to what validation data was used when the document was first verified."

In version 1 there are three profiles that have different levels of detail in their structure: Basic (B), Comfort (C) and Extended (X): https://mind-forms.de/e-rechnung/welches-zugferd-profil-kann-ich-verwenden/ 

The issue may be reproduced by opening the attached PDF in Adobe Reader. Although the viewer initially shows the characters correctly, when you start typing in the TextBox, the umlaut/diacritics characters get corrupted. In other PDF viewers, the umlaut characters are handled correctly, so the issue seems to related to concrete Adobe Reader encoding handling implementation. The diacritic characters are handled incorrectly in other viewers as well (e.g. Chrome).

When a Pdf document contains TextBoxFields some of which are hidden and you merge it with another document, the hidden state is reset and the field appears in the merged document:

Before:

After:

 

Add support for /TR (Transfer Function) property of SMask.

Importing document containing TextBox widgets with NormalContentSource defining text properties, such as FontSize and Position, are exported with incorrect appearance when the value of the field is modified.

Add support for the PAdES-BES signature standard

Solid lines appear over dashed lines when generating PDF from SVG diagram.

OutOfMemoryException is thrown when importing a large document with invalid cross-reference table.

Creating a document from an SVG image with a CapPathRound (stroke-linecap="round") adds unexpected lines.

MissingMethodException is thrown when converting a PDF stream to a PdfArray.

The appearance of a form field button is lost after import-export.

The CIDToGIDMap value is exported as an indirect object. When the value is a PdfString ist should be directly exported and not referred as an indirect object. 

When writing a RadFixedPage containing widgets using the PdfPageStreamWriter.WriteContent() method an exception is thrown.

The exception: System.ArgumentNullException: 'Value cannot be null. Parameter name: context'