I just updated my system to Ubuntu 16.10 / GNOME Shell 3.20.4 and I see that this extension does not work anymore:
How can I help you to make it work on 16.10?
To install it, first do:
gsettings set org.gnome.shell disable-extension-version-validation "true"
But, to make the change at the extension level, making it work with new gnome-shell version is just a matter of editing metadata.json I guess.
Yes, what is strange is that the metadata.json file already contains 3.20:
I guess the version uploaded to GNOME Shell website is older...