This article currently (2021) contains only instructions for updates that were required years ago, and should no longer be needed. If a more involved upgrade (that requires instructions) happens again, it should be accompanied by a corresponding news item (that should be read and followed), and may also get a new entry here.
polkit changed its rules and actions file format. See the polkit man page for more informations. Actions are now in /usr/share/polkit-1/actions, rules now in /usr/share/polkit-1/rules.d and /etc/polkit-1/rules.d.
For the rationale and more informations see David Zeuthen's blog post.