Hi there, if the theme folder has been updated and WordPress is currently running 4.0 then it should work fine. Try disabling the plugins incase its a plugin conflict causing the site to go down. If you have access to the WP menu then you should be able to do this through there, if you don’t then go into your hosting via ftp or cpanel and rename the plugin folder temporarily and see if the site comes back. Then it will be a case of enabling each plugin one by one to see which is causing the white screen issue.