Adding and removing Jupyter kernels

 Using the following command to see the currently installed kernels:

jupyter kernelspec list

And the following command to remove an installed kernel (in my case an updated version has been installed):

jupyter kernelspec uninstall julia-1.9

To add an updated version of Julia kernel into Jupyter, it is sufficient to:

Pkg.build("IJulia")

These simple things need to become part of my muscle memory.