Added
- Add `parcoords` trace type (parallel coordinate plots) [[1256](https://github.com/plotly/plotly.js/pull/1256)]
- Add support for multiple range sliders [[1355](https://github.com/plotly/plotly.js/pull/1355)]
- Add `'aitoff'` and `'sinusoidal'` geo projection types [[1422](https://github.com/plotly/plotly.js/pull/1422)]
- Implement `scene.dragmode: false` to disable drag interaction on 3D subplots
[[1377](https://github.com/plotly/plotly.js/pull/1377)]
- Add `showAxisDragHandles` and `showAxisRangeEntryBoxes` configuration options
[[1389](https://github.com/plotly/plotly.js/pull/1389)]
- Add `customdata` attribute to scatter traces to add custom data to scatter SVG
nodes [[1379](https://github.com/plotly/plotly.js/pull/1379)]
Changed
- Consistent handling of array containers during `relayout` [[1403](https://github.com/plotly/plotly.js/pull/1403)]
- Improve hover for `choropleth` traces [[1401](https://github.com/plotly/plotly.js/pull/1401)]
- Make range slider handles and mask crispier [[1409](https://github.com/plotly/plotly.js/pull/1409)]
- Bump `country-regex` dependency to `1.1.0` [[1392](https://github.com/plotly/plotly.js/pull/1392)]
Fixed
- Fix 3D on iOS devices [[1411](https://github.com/plotly/plotly.js/pull/1411)]
- Fix `surface` trace opacity scaling [[1415](https://github.com/plotly/plotly.js/pull/1415)]
- Fix hover data in animations [[1274](https://github.com/plotly/plotly.js/pull/1274)]
- Fix annotations edit when dragging from one axis to another [[1403](https://github.com/plotly/plotly.js/pull/1403)]
- Fix 3D hover labels for date axes [[1414](https://github.com/plotly/plotly.js/pull/1414)]
- Deleting cartesian subplots now clear their corresponding axis titles [[1393](https://github.com/plotly/plotly.js/pull/1393)]
- Fix hover for xyz column `heatmap` trace `'text'` [[1417](https://github.com/plotly/plotly.js/pull/1417)]
- Fix `scattermapbox` lines with trailing gaps [[1421](https://github.com/plotly/plotly.js/pull/1421)]
- Make `restyle`, `relayout` and `update` not mutate input update objects [[1376](https://github.com/plotly/plotly.js/pull/1376)]
- Fix race condition in gl2d `toImage` [[1388](https://github.com/plotly/plotly.js/pull/1388)]
- Fix handling of `Virgin Islands` country name [[1392](https://github.com/plotly/plotly.js/pull/1392)]
- Fix `Plotly.validate` for `colorscale` attributes [[1420](https://github.com/plotly/plotly.js/pull/1420)]