Fatal error: Uncaught Error: Call to undefined function wp_is_valid_utf8() in /mnt/web508/d1/87/510844787/htdocs/STRATO-apps/wordpress_07/app/wp-includes/formatting.php:2291
Stack trace:
#0 /mnt/web508/d1/87/510844787/htdocs/STRATO-apps/wordpress_07/app/wp-includes/class-wp-taxonomy.php(378): sanitize_title_with_dashes()
#1 /mnt/web508/d1/87/510844787/htdocs/STRATO-apps/wordpress_07/app/wp-includes/class-wp-taxonomy.php(290): WP_Taxonomy->set_props()
#2 /mnt/web508/d1/87/510844787/htdocs/STRATO-apps/wordpress_07/app/wp-includes/taxonomy.php(532): WP_Taxonomy->__construct()
#3 /mnt/web508/d1/87/510844787/htdocs/STRATO-apps/wordpress_07/app/wp-includes/taxonomy.php(63): register_taxonomy()
#4 /mnt/web508/d1/87/510844787/htdocs/STRATO-apps/wordpress_07/app/wp-settings.php(513): create_initial_taxonomies()
#5 /mnt/web508/d1/87/510844787/htdocs/STRATO-apps/wordpress_07/app/wp-config.php(110): require_once('...')
#6 /mnt/web508/d1/87/510844787/htdocs/STRATO-apps/wordpress_07/app/wp-load.php(50): require_once('...')
#7 /mnt/web508/d1/87/510844787/htdocs/STRATO-apps/wordpress_07/app/wp-blog-header.php(13): require_once('...')
#8 /mnt/web508/d1/87/510844787/htdocs/STRATO-apps/wordpress_07/app/index.php(4): require('...')
#9 {main}
  thrown in /mnt/web508/d1/87/510844787/htdocs/STRATO-apps/wordpress_07/app/wp-includes/formatting.php on line 2291