Hi Brad,
Thanks for reaching out, and I’m so sorry for the trouble here! Our latest available version for Events Calendar PRO is version 4.4.15 as of this writing–if your client is indeed using version 4.1.2 and WordPress is not prompting them to install a newer version, they may need to try downloading the latest version of the plugin from their account’s Downloads page and installing it manually. Sometimes “stuck” plugins can also be prompted to check for updates by installing another plugin from the WordPress.org plugin repository. Simply download and install any plugin from your WordPress admin, then return to your plugins listing and check to see if any plugins are requesting updates. You can delete the new plugin once this process has been completed.
If you’re still having trouble after following these steps, our technical support team would be glad to assist over in our premium forums. Please don’t hesitate to log in and submit a post to our Events Calendar PRO forum! 🙂
I hope that helps to get you started here! Thanks again, and let us know if there’s anything else that we can do for you!