The CurrentPageTextBox in the toolbar has stopped displaying in the latest version.

Workaround: 

<telerik:CurrentPageTextBox x:Name="PART_CurrentPageNumberTextBox" 
                            HorizontalContentAlignment="Center" 
                            Margin="2" Text="{Binding FixedDocumentViewer.CurrentPageNumber, Mode=TwoWay}"
                            VerticalContentAlignment="Center" Width="45" 
                            telerik:StyleManager.Theme="Office_Black"/>

The thinnest line thickness is thinner than in Adobe and it is not scaled according to the scale factor.

Observed:

When importing a document with empty pages collection an ArgumentNullException: 'Value cannot be null.
Parameter name: page', is thrown, which leads to application crash.

Workaround: Import the document using the PdfProcessing library and add an empty page:

Document cannot be loaded because the Encrypt property is not set and is null.

The UserDict collection is not parsed and the procedures for the operators are unavailable. The exception is thrown while trying to read the font file of the Univers and Univers Bold fonts.

Internally, an ArgumenNullException is thrown, which results in missing content when the document is shown in RadPdfViewer.

All annotations are missing because ArgumentNullException is thrown while importing page annotations. The exception is handled and all non-annotation related pdf content is loaded successfully.

When importing document containing a destination which points to invalid page reference, KeyNotFoundException is thrown.

When a page is rotated its annotations are not positioned correctly. 

When the file has an annotation with a destination and this destination is missing from the destinations (Dests) collection of the catalogue, KeyNotFoundException is thrown when you try to scroll to the page where the annotation is located. A better behavior would be for nothing to happen when trying to click on the annotation leading to the destination.