I just attempted to update the Ruby Plugin in IntelliJ by right clicking the installed plugin (which had a ! icon) and selected update.
However, when I restarted Idea the plugin was completely removed and Idea was to treat my ruby module as a java module.
I then installed the ruby plugin (as if afresh) without issue.
So ... so big deal here, just that the update option doesn't work.
Idea #9886, updating ruby plugin from 2.0.235166 to 2.0.236202