Thanks for asking.
Looks like your website is validated now. Please see screenshots in secure note.
To update Cornerstone and X Theme please take a look at following resources:
Version compatibility guide: To learn about the latest and compatible versions of bundled and supported plugins, please take a look at following doc:
2. Theme Update guide: Please take a look at following article to update Cornerstone.
3. Please take a look at following doc about changelog: