Fatal error: Uncaught Error: Call to undefined function username_exists() in /httpdocs/wp-includes/version.php:100 Stack trace: #0 /httpdocs/wp-settings.php(29): require() #1 /httpdocs/wp-config.php(89): require_once('/httpdocs/wp-se...') #2 /httpdocs/wp-load.php(37): require_once('/httpdocs/wp-co...') #3 /httpdocs/wp-blog-header.php(13): require_once('/httpdocs/wp-lo...') #4 /httpdocs/index.php(18): require('/httpdocs/wp-bl...') #5 {main} thrown in /httpdocs/wp-includes/version.php on line 100