Update: version 4.9 has been released since this was posted.
Hi everyone! This week we released Plotly.py 4.4.1 to PyPI and Conda. This was a Python-only release which doesn’t include a new big version of Plotly.js, and we hope you enjoy the new features and bug-fixes! The changelog remains the complete reference for this release, but read on for the highlights!
Get it now with pip install plotly==4.4.1 or conda install -c plotly plotly=4.4.1 
7 New Plotly Express Functions
As part of our long-term project to make Plotly Express a more complete high-level interface for making figures of all kinds, we’re continuing to add top-level px functions:
px.pieby popular demandpx.sunburstandpx.treemapfor hierarchical part-of-whole visualizationspx.funnelandpx.funnel_areafor two ways of visualizing process stagespx.choropleth_mapboxandpx.density_mapboxto match this summer’s new mapping traces
Some New Plotly Express Arguments
All of the px.*_polar functions now accept a range_theta argument, for when you want to plot less than a full circle. Also, all of the px.*_mapbox functions now accept center just like the px.*_geo functions, and in addition, they accept mapbox_style so you can more-easily make tile maps without needing a Mapbox.com token.
Reversible Colorscales
You can now add _r to the name of any of our built-in continuous colorscales to get a reversed version of the colorscale e.g. Viridis/Viridis_r or Reds/Reds_r etc.
Documentation Improvements
Our docstrings are now doc-tested, so you can be sure that code snippets within docstrings will run correctly. In addition, we’ve moved all of the Plotly Python Graphing Library documentation source files into the main Plotly.py repo so as to be able to keep code and docs in closer sync. This should allow us to avoid some regressions and ensure faster turnaround on documentation for new features.
Plotly Express Default Height Change
We discovered that Dash users were encountering problems using Plotly Express in their apps because px.defaults.height was set to 600, so we decided to change this to None by default. This means that px-generated figures will generally auto-size themselves to be 450 pixels tall in Notebooks and other contexts by default. You can get the old behaviour back by setting px.defaults.height=600 once per session, or passing height=600 as an argument to any px function.
Thanks
Thanks to community contributors dev-dsp and joelostblom!