An ArgumentNullException is thrown when importing a document with a missing required MediaBox operator in the Page object ("ArgumentNullException: 'Value cannot be null.")

RadPdfProcessing currently supports interactive forms whose data is defined directly in the document. To preserve them when importing and exporting documents, add support for import-export interactive forms based on the Adobe XML Forms Architecture (XFA).

From PDF 2.0 the XFA forms are depreciated.

SkiaImageFormatProvider: Add support for Text, TextMarkup, Line, and Stamp annotations.

Currently, these annotations are omitted on image export.

It would be beneficial for the clients if every cell has this "cached value" even if the formula can't be evaluated for some reason with the SpreadProcessing - no need for recalculation, just reading the value. It should read the last values while the document was being saved at the originator.

Getting a method like "GetCachedValueString ..." , ideal with the same formatting used for the cell and localization, would be helpful. 

Handle import of documents with wrong type of action key.

Once this is completed use the Exceptions Handling mechanism to handle this scenario. For instance:

private void ImportSettings_DocumentUnhandledException(object sender, DocumentUnhandledExceptionEventArgs e)
{
    if (e.Exception is InvalidActionException)
    {
        

Currently, a NullReferenceException is thrown because of the incorrect structure. 

As a workaround, the exception can be handled using the Handling Exceptions mechanism.

Update:
When importing documents with invalid structure of path construction operators an InvalidGraphicOperandsCountException is thrown which could be handled using the Handling Exceptions mechanism.

PdfFormatProvider provider = new PdfFormatProvider();
provider.ImportSettings.DocumentUnhandledException += this.ImportSettings_DocumentUnhandledException;

private void ImportSettings_DocumentUnhandledException(object sender, DocumentUnhandledExceptionEventArgs e)
{
    if (e.Exception is InvalidGraphicOperandsCountException)
    {
        e.Handled = true;
    }
}

ZUGFeRD (acronym for Zentraler User Guide des Forums elektronische Rechnung Deutschland) is a specification for the electronic invoice format of the same name.

The feature depends on the following features:

• Support for embedded file streams
• Support for metadata streams (XMP metadata)

Add support for extraction of AES-encrypted archives.

There is a related feature request for the creation of such archives: ZipLibrary: Add support for creation of AES-encrypted archives.

Handle import of documents with self-referring styles.

As a workaround, you can go through the RTF document structure of a single file and utilize Regex to resolve the self-referring styles like this:

string rtf = File.ReadAllText("inputFile.rtf");
rtf = FixSelfReferringStyles(rtf);

Telerik.Windows.Documents.Flow.FormatProviders.Rtf.RtfFormatProvider provider = new Telerik.Windows.Documents.Flow.FormatProviders.Rtf.RtfFormatProvider(); 

 var document = provider.Import(rtf);

...

private static string FixSelfReferringStyles(string rtf)
{
    string regexString = @"{\\s([0-9]+)[^}]*\\slink([0-9]+)";

    var matches = Regex.Matches(rtf, regexString);
    foreach (Match match in matches)
    {
        if (match.Groups[1].Value == match.Groups[2].Value)
        {
            var oldValue = match.Groups[0].Value;
            var newValue = oldValue.Replace(@" \slink" + match.Groups[1].Value, string.Empty);
            rtf = rtf.Replace(oldValue, newValue);
        }
    }

    return rtf;
}