All jupyter contrib nbextensions are marked as possibly incompatible

I have just installed jupyter_contrib_nbextensions by:

pip install jupyter_contrib_nbextensions
jupyter contrib nbextension install --user

When I open a jupyter notebook and navigate to Edit -> nbextensions config, I see the below screen:

All extensions are marked as "possibly incompatible". A solution is to uncheck the option: "disable configuration for nbextensions without explicit compatibility". But is it safe? Any ideas why the nbextensions are incombatible?

My package versions are:

jupyter==1.0.0
notebook==6.0.1
jupyter-contrib-nbextensions==0.5.1

As you will notice, in version 0.5.1 of jupyter_contrib_nbextensions most of the nbextensions are compatible with versions 4.X and 5.X. For example look at this extension:

It you uncheck the option "disable configuration for nbextensions without explicit compatibility", you will most probably have no problem using any extension. I guess that the developers haven't yet tested the jupyter_contrib_extensions against the new notebook version 6.X which was recently launched. If you want to have a stable and tested environment, you can roll back to a previous jupyter notebook version. The most recent compatible one is 5.7.8. Just uninstall current notebook and install that specific version by executing:

pip uninstall notebook
pip install notebook==5.7.8