Fatal error: Uncaught Error: Call to undefined function wp_is_valid_utf8() in /home/site/wwwroot/wp-includes/formatting.php:2287
Stack trace:
#0 /home/site/wwwroot/wp-includes/class-wp-taxonomy.php(378): sanitize_title_with_dashes('category_name')
#1 /home/site/wwwroot/wp-includes/class-wp-taxonomy.php(290): WP_Taxonomy->set_props('post', Array)
#2 /home/site/wwwroot/wp-includes/taxonomy.php(532): WP_Taxonomy->__construct('category', 'post', Array)
#3 /home/site/wwwroot/wp-includes/taxonomy.php(82): register_taxonomy('category', 'post', Array)
#4 /home/site/wwwroot/wp-settings.php(513): create_initial_taxonomies()
#5 /home/site/wwwroot/wp-config.php(133): require_once('/home/site/wwwr...')
#6 /home/site/wwwroot/wp-load.php(50): require_once('/home/site/wwwr...')
#7 /home/site/wwwroot/wp-blog-header.php(13): require_once('/home/site/wwwr...')
#8 /home/site/wwwroot/index.php(17): require('/home/site/wwwr...')
#9 {main}
thrown in /home/site/wwwroot/wp-includes/formatting.php on line 2287