Websites are not loading.
The following error can be found in website log
PHP Fatal error: Call to undefined function import_request_variables() in /var/www/vhosts/example.com/httpdocs/index.php on line 33
Code optimized for another PHP version.
Switch website to PHP 5.3 in Plesk > Domains > domain_name > Hosting Settings : choose FastCGI handler and select
php 5.3 from drop-down menu.