Thanks @beckej – the Donham error I understand (it’s a problem we created), but I’m confused as to why you’re not able to update McLuhan, which does have a 2.11.1 version released, tagged, and available via GitHub: Release McLuhan 2.11.1 · pressbooks/pressbooks-book · GitHub. Does the method described by @figureone earlier
I was able to update successfully after refreshing the GitHub Updater plugin cache (Dashboard > Settings > Github Updater > Refresh Cache)
change anything for you with that theme?