Added new arc diagram series which visualizes the relationship between data set nodes.
Added breadcrumb functionality for drilldown charts as well as hierarchical series including treemaps and sunburst. This replaces the drill-up and traverse-up buttons
Added new chart.alignThresholds feature for aligning the thresholds in charts with multiple axes.
Added new hangingIndentTranslation and minNodeLength options for Organization chart, for improving the layout of deep structures.
Added new Highcharts.AST.bypassHTMLFiltering option for disabling AST filtering.
Added boost.pixelRatio option which provides Retina and device pixel ratio support to the Boost module.
Added areaspline series to the supported series in the Boost module.
Added support for non-ASCII characters (Chinese, Russian etc) in exported PDFs via new exporting.pdfFont property.
Added smarter defaults for accessible point descriptions.