Adds new treegraph and pictorial series types.
Features
- Improved the design with a clearer, more vivid palette, added contrast for text labels and many minor visual changes.
- Added new treegraph and pictorial series types.
- Removed support for Microsoft Internet Explorer 8 and older.
- Changed the default builds to ECMAScript version ES2016.
- Replaced SASS files for styledMode with updated CSS files. Highcharts theming is now easier by supporting CSS variables as well as prefers-color-scheme.
- Sonification module v2 with many new features for audio charts is now part of the official API.
- Changed default rotationMode to circular for sunburst data labels.
- Added minorTicksPerMajor option for axes.
- Added the point.percentage property for gauge charts.
- Added ResizeObserver to the chart so it could adjust reflow on container size change.
