FWIW, if users have problems with ipywidgets there appears to be a bigger issue with ipywidgets not working in latest v.
jupyter-widgets/ipywidgets#669 (comment)

I did manage to get ipywidgets to run using:
~/.local/bin/jupyter nbextension enable --py widgetsnbextension
and then
~/.local/bin/jupyter notebook

I hope the above helps someone.