By specification, the last line of the file contains only the end-of-file marker, %%EOF. If the file contains many trailing bytes at its end, a NotSupportedException: 'StartXRef keyword cannot be found.', is thrown.

Workaround: Trim any content after the end-of-file marker (see FixInvalidEndOfFile). 

Add support for documents containing RTL (right-to-left) text.

Implement importing and exporting the javascript actions associated with push button fields so that they can be executed when the exported document is opened with Adobe Acrobat. Javascript actions are also used by text fields for text validation (for instance for date input).

Currently, NotSupportedEncryptionException is thrown.

This would allow to encrypt documents only with Owner Password and not showing password dialog when disabling some PDF features permissions. The customer should be able to disable printing, text and graphic selection and extraction, page rotations and others. The full specification of all permission bits may be seen in Table 3.20 on page 124 in PdfReference 1.7. On page 120 in PdfReference 1.7 are described the User and Owner passwords.

When merging documents containing the same embedded font every time a document is merged the same font is repeatedly embedded in the merged document. This leads to very large files.

A possible workaround before this feature is developed could be to use the PdfProcessing model to import and merge the documents. After the documents are merged to iterate the document`s content in order to cache the fonts using their name and if there are duplicated names to set the already cached one (check the attached project). 

As a side note, the suggested workaround doesn't cover all possible cases (e.g. if there are fonts with a common name but different font sets (modified fonts or font subsets) this may lead to missing/different characters in the produced document). So in order to use this workaround, you will need to ensure the font names are unique for every different font.

For example when some PDF file has uncompressed contents we may import it and apply better compression to the stream objects. Ensure that all the content inside the document is compressed.

When a TrueType font is defined, the mapping of character codes to glyph indices depends on the built-in cmap table mappings defined in the font and the Encoding property defined in the PDF dictionary.

However, the current implementation maps all characters with cmap tables for Microsoft Symbolic and Macintosh Roman, which causes incorrect mapping results, e.g. space characters are mapped to an Ê glyph.

The issue is also described in the following public item: TryGetCharCode for OpenTypeFont uses wrong cmap and returns wrong charcode.

Workaround: Change the font  of the TextBoxField's widget appearance:
foreach (var widget in field.Widgets)
{
    widget.TextProperties.Font = FontsRepository.Helvetica;
}

When merging documents` pages using the PdfStreamWriter the Form Fields are not copied:

using (PdfStreamWriter fileWriter = new PdfStreamWriter(File.OpenWrite(document2Name)))
{
	// Iterate through the files you would like to merge 
	for (int i = 0; i < 2; i++)
	{
		// Open each of the files 
		using (PdfFileSource fileToMerge = new PdfFileSource(File.OpenRead(document1Name)))
		{
			// Iterate through the pages of the current document 
			foreach (PdfPageSource pageToMerge in fileToMerge.Pages)
			{
				// Append the current page to the fileWriter, which holds the stream of the result file 
				fileWriter.WritePage(pageToMerge);
			}
		}
	}
}

A possible workaround is to use the RadFixedDocument`s Merge() method: 

document1.Merge(document2);

When using the Telerik.Documents.ImageUtils.JpegImageConverter default implementation in Blazor WebAssembly application the Magick.NET library doesn't load all of its assemblies.

Workaround:
Create a custom implementation of the JpegImageConverterBase class: Create Custom JpegImageConverter in .Net Standard.