@rellwood
You can always forgo the automatic installer (beta testers do this)
Download from the selected Plugins forum thread. (

I add the release # to the end of the file name in my
archive the PI folder ) , That way I have previous versions (I do delete those that have Known issues, so I don't ever try those again)
You do it the old way (before
Get Plugins era)
Preferences:Plugins: Load from File (a button, lower right) If downgrading a previous,
find and select from the Installed List: Click the
Remove Plugin (button)
I prefer to restart Calibre, before installing a lower version, just to have a clean slate.