The Notre Dame Sites network has been updated to 5.5 which focused on three major areas: speed, search, and security. Read more about the WP 5.5 release.
As mentioned earlier, the Block Editor has become the default on sites.nd.edu. Visit wordpress.org/gutenberg to learn more about the WordPress block editor. If you would like to have the option for the Classic Editor, you can activate it in your Plugins settings.