Bokeh 1.3.1, a hotfix to address a serious bug with PNG export, is released.
If you are using Anaconda/miniconda, you can install it with conda:
conda install -c bokeh bokeh
Alternatively, you can also install it with pip:
pip install bokeh
Since I forgot to make an announcement post for 1.3 in all that is going on lately, I will also note the link to that announcement here: