v1.21.1

Fixed

• Fix ms2datetime routine for Chinese calendar [#1252]
• Fix tickformat for world calendars [#1252]

v1.21.0

Added

• Bar labels via text and textposition [#1159]
• Add support for 16 non-gregorian calendars for date inputs and display [#1220,
  #1230, #1237]
• Add support for ISO-8601 timestamps [#1194]
• Extend histogram bin auto-shifting algorithm to date axes [#1201]
• Trace type heatmapgl is now included in the main plotly.js bundle [#1197]

Changed

• Linearize date coordinates using UTC rather than local milliseconds [#1194]

Fixed

• Fix wrongly computed date positions around daylight savings time [#1194]
• Fix erroneous traces in multi-subplot layout containing fill-to scatter
  traces (and plotly.py violin plots) [#1198]
• Fix clip path URL on pages with query hashes [#1203]
• Ensure that numeric frame name are handle correctly [#1236]
• Fallback for manual manipulation of slider/frames [#1233]

v1.20.5

Fixed

• Fix 1.20.0 regression in handling numerical strings including commas and spaces
  [#1185]
• Fix 1.20.0 regression involving date histograms [#1186]
• Fix numerous tickvalsandticktext` edge cases [#1191]

v1.20.4

Fixed

• Fix metaKeys field in PlotSchema.get() output

v1.20.3

Fixed

• Remove infinite loop when plotting 1-pt scattergl traces [#1168]
• Fix updatemenu bug where the wrong button was set to active [#1176]
• Fix addTraces when called with existing traces as input [#1175]

v1.20.2

Fixed

• Fix hover labels in stacked bar charts [#1163]
• Fix mode bar zoom buttons on date axes [#1162]

v1.20.1

Fixed

• Fix annotation positioning on categorical axes [#1155]

v1.20.0

Added

• Allow date string inputs for axis ranges, tick0, dtick, annotation / image
  positions, histogram bins [#1078, #1150]
• Add special dtick values for log axes [#1078]
• Add visible attribute to annotations, shapes and images items [#1110]
• Expose events on slider start/change/end [#1126]
• Expose event on updatemenu button click [#1128]
• Allow custom transform module to have supply layout default handler [#1122]

Changed

• Increase scattergl precision [#1114]
• Use topojson-client to convert topojson to geojson [#1147]

Fixed

• Fix hover labels for multi-trace scattergl graphs (bug introduced in
  1.18.0) [#1148]
• Fix date format on hover on full hour [#1078]
• Fix bar labels for non-zero base values [#1142]
• Scatter colorscale now yield correct colors when cmin and cmax ashow re equal
  [#1112]
• Fix filter transform for categorical target arrays with range operations
  [#1120]
• Make sure frames with null values clear array containers [#1118]
• Fix animations involving trace opacity [#1146]
• Fix fallback for non-animatable trace modules (bug introduced in 1.18.1)
  [#1141]
• Fix race condition in animation resolution when coupled with relayout
  [#1108]
• Enforce casting requested frame names to strings [#1124]
• Plotly.animte no longer breaks when passing null frames [#1121]
• Plotly.PlotSchema.get now correctly list rangeslider and rangeselector under
  xaxis only [#1144]
• Plotly.relayout correctly updates arbitrary layout attributes [#1133]

v1.19.2

Fixed

• Fix hover label positioning on bar traces [#1107]

v1.19.1

Fixed

• Fix dist bundles [#1094]