See v7 migration guide for information on the breaking changes.

• A new and improved default UI that is structured a bit differently. The previous UI is still accessible with the constructor option ui: 'legacy'.
• All APIs now take 1-indexed page numbers. Previously some APIs would take 0-indexed page numbers.
• Search constants have been moved to the CoreControls namespace.
• PartRetriever classes can no longer be access directly, they should be used through the getPartRetriever API
• A few rarely used CanvasManager APIs have been removed: Core.CanvasMode, Core.setCanvasMode, DocumentViewer.setPagesPerCanvas, DocumentViewer.returnCanvas

• Added support for threaded WebAssembly. This means performance improvements by being able to render and process document pages and actions in parallel.
• Added a text comparison sample which shows how you can compare changes in the text of two different documents.
• Updated the RubberStampCreateTool to allow the creation of custom stamps.
• Updated the RubberStampCreateTool to allow setting a list of default stamps and custom stamps. These lists are used by default in the UI.
• Added a count measurement tool which will track the number of count annotations on the document.
• Properties and constants now consistently use the same casing throughout the WebViewer APIs. For example Namespace.MY_CONSTANT. The previous casings still remain for backwards compatibility.
• Added APIs to allow a custom appearance to be set on annotations when the PDF is downloaded
• Part retrievers are now split out from CoreControls.js and lazy loaded when needed.
• Added support for displaying polyline line endings
• Added annotation.isPrintVisible to check if annotation is visible when printing
• Added AnnotationManager.getCopiedAnnotations API to get the list of annotations that are currently copied
• Added a historyChanged event to AnnotationHistoryManager as well as the canUndo and canRedo functions.
• Added a getContents API to the FreeText editor instance
• Added a multiplier option to doc.loadCanvasAsync which changes the scaling factor for that particular loadCanvasAsync call
• Added a fitText API to FreeText and Callout annotations to programmatically fit the annotation to the text so that all text is visible
• Added a new event that is fired when the active search result has changed
• Added the useDisplayAuthor option to exportAnnotations so that the XFDF string will contain the mapped user display names.
• Added an optimized version of PDFNet.js that is significantly smaller than the default script by removing function type checks and warnings. It can be used by running the optimize script .
• Allow PDFDoc objects to be passed at the same time as the pdftronServer option and have them automatically uploaded to the server
• Updated so that if the option streaming: false is explicitly passed then there will be no check for whether the server support byte ranges or not

• Fixed many office file rendering issues.
• Fixed many incorrect types in the TypeScript declaration file.
• Fixed issue where images with built in orientation data weren't being displayed upright in all browsers.
• Fixed issue where widgets with the same name were not showing the formatted value correctly
• Fixed issue where switching to a different tool when making a highlight annotation would leave the highlight annotation in the document
• Fixed issue where deleting widgets from the document wasn't removing the field's reference to the widget
• Fixed issue where rich text editor wasn't focused the first time in iOS devices
• Fixed issue where XOD files as Cordova file objects weren't able to be loaded
• Fixed issue where typing in certain text areas in PDF causes the screen to flicker in IE11
• Fixed issue with accented characters in freetext annotations being cut off
• Fixed issue where annotations with the NoView property were not able to be printed
• Fixed issue where documents whose content streams were incorrectly marked as compressed object streams weren't able to be downloaded
• Fixed issue where undo/redo of a FreeText annotation would throw a warning message about appearance render
• Fixed issue where searching did not work in some XOD files
• Fixed issue where signature appearance wasn't displayed for older XOD files
• Fixed issue where setting the dropdownbox list via embedded JS did not work properly
• Fixed issue where entity elements in XFDF could cause the XML parser to lock up
• Fixed exportAnnotCommand so it doesn't throw an error after a widget is created
• Fixed issue where calling getFileData on a doc instance that is created by Core.createDocument would throw an error
• Fixed issue with the overrideSelection property on tools
• Fixed issue where some date formats weren't accepted by date fields

• New default user interface with improved grouping of tools and organization of components.
• Added UI for creating custom stamps with different text, colors, date, time and user name.
• Added a setCustomModal API
• Added a count measurement tool button in the measurement group.
• Updated the search panel to use a virtualized list for improved performance with many search results.
• Added support for changing the color of signatures as they are created.
• Added API to customize annotation tooltips
• Added option to include or exclude annotation when printing
• Added the MouseWheelZoom feature which allows disabling of zooming with the mouse wheel

• Fixed issue where the aspect ratio of thumbnails wasn't preserved in some cases
• Fixed issue where the annotation layer that overlaps the thumbnails wasn't exactly aligned with the page content
• Fixed issue where you can type past max/min zoom level and exposed APIs to get max/min zoom level
• Fixed the swipe threshold so that swiping the pages worked better
• Fixed issue with disabling FreeText editing on the page not working as expected
• Fixed issues with configorigin.txt when the origin was null