When WordPress initially released their block editor (Gutenberg), we made the decision to continue with the Classic editor for the Notre Dame blogs network. This was done by activating the “Classic Editor” plugin for the entire network, with the option for site admins to enable the block editor for their sites.
Starting with the WordPress 5.5 update slated for August 2020, the Classic Editor will be disabled by default for the entire network. Site admins will have the option of reactivating the plugin for their site if they wish.
Visit wordpress.org/gutenberg to learn more about the WordPress block editor.