Fatal error: Uncaught Error: Class "IXR_Client" not found in /var/lib/sites/site-1049/www/html/wp-includes/IXR/class-IXR-clientmulticall.php:8
Stack trace:
#0 {main}
  thrown in /var/lib/sites/site-1049/www/html/wp-includes/IXR/class-IXR-clientmulticall.php on line 8