- Sankey diagram with new trace type `sankey` [#1591, #1664]

- Add `hoverlabel` trace and layout attributes to customize hover label colors

and fonts [#1582]

- Add `marker.gradient` attributes for `scatter`, `scattergeo`, `scatterternary`

and `scattercarpet` traces [#1620]

- Add `sort` transform [#1609]

- Add `preservegaps` `filter` transform attribute [#1589]

- Add `!=` (not equal) `filter` transform operation [#1589]

- Add `labelfont`, `tickfont` and `rangefont` attributes for `parcoords` traces

[#1624]

- Pass DOM mouse event on `plotly_clickannotations` events [#1652]

- Performance optimization for range sliders and Drawing cache [#1585]

- Fix `scattergl` marker symbol positioning (bug introduced in 1.25.0) [#1633]

- Fix gl2d zoom where two clicks would trigger a zoom box (bug introduced 1.26.0) [#1632]

- Fix legend double click handler for `carpet` traces [#1636]

- Fix `restyle` for `scattercarpet` for style attributes with array support [#1641]

- Fix `restyle` for array layout components when more than 10 items are present

[#1639]

- Fix select-box and lasso selections so that they don't include bad-data items

[#1656]

- Fix `restyle` for contour `zmin` and `zmax` [#1653]

- Fix `scatter` text node transitions [#1616, #1626]