Hello Alan Scott that version of WordPress is very old and your site could be hacked in the future.
I know that you are aware of this. If I were you I would do what ever it takes to promptly update it. I just thought of sharing this as I care about peoples websites.
You might have to use an earlier version of the plugin as this latest version might crash your website. Make sure that you have a latest backup before you go ahead and test the plugins latest version.
Kind regards