Remove Yoast SEO upgrade notices

functions.php

<?php

// add to your functions.php

add_action('admin_init', 'theme_disable_yoast_notifications');
	
function theme_disable_yoast_notifications() {
  
  if ( is_plugin_active( 'wordpress-seo/wp-seo.php' ) ) {
    
    remove_action( 'admin_notices', array( Yoast_Notification_Center::get(), 'display_notifications' ) );
    remove_action( 'all_admin_notices', array( Yoast_Notification_Center::get(), 'display_notifications' ) );
    
  }
  
}