It’s amazing the little things you can learn when you RTFM. Like the other day when I came across mention of a new command in the RubyGems gem program (version 0.91 or newer) which makes it easy to check against a remote repository to see if your installed gems are up-to-date.
The command is straightforward: sudo gem outdated
You’ll get a nicely output list of your outdated installed gems showing the current version followed by the most recent version number. The usual gem update procedures apply from there. Happy updating!