Google Search Console sent out another round of alerts to both WordPress users and Joomla users where they discovered that the site is running an older version of the CMS.
Google sent out emails to affected webmasters, but it will also show up in Google Search Console messages for the affected sites.
If you have upgraded or changed platforms, you don’t need to let Google know, and it doesn’t affect your search rankings to be using an outdated CMS. But if you end up getting hacked, which is much more likely to happen when you run an outdated version of WordPress, Joomla or any related plugins/addons, then that can affect your rankings. This is because Google can remove your site from the search if they discover it has been hacked, show the red alert interstitial or show the “This site may be hacked” flag in the search results.