Nginx – After upgrade of NGINX and PHP-FPM, PHP stopped working and there is no error anywhere

PHP-FPM is running, NGINX is running. NGINX does read the socket for PHP-FPM. I stopped PHP-FPM and I got bad gateway error. However, nothing gets displayed. I have checked nginx/error.log and php5-fpm.log and there is no error regarding that.

I changed logging in PHP-FPM to see what is happening and based on requests it creates child processes as needed (pm=ondemand).

Here is my php-fpm.conf:

pid = /var/run/php5-fpm.pid
error_log = /var/log/php5-fpm.log
log_level = debug
include=/etc/php5/fpm/pool.d/*.conf

pool.d/www.conf (the only file there)
[www]
user=www-data
group=www-data

listen=/var/run/php5-fpm.sock
listen.owner=www-data
listen.group=www-data

pm=ondemand
pm.max_children=4
pm.start_servers=2
pm.min_spare_servers=1
pm.max_spare_servers=3
chdir=/

and here is nginx.conf

user www-data www-data;
worker_processes 4;
pid /run/nginx.pid;

events {
    worker_connections 768;
}

http {
    client_max_body_size 32M;
    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 65;
    types_hash_max_size 2048;
    include /etc/nginx/mime.types;
    default_type application/octet-stream;

    access_log /var/log/nginx/access.log;
    error_log /var/log/nginx/error.log;

    gzip on;
    gzip_disable "msie6";
    upstream php {
        server unix:/var/run/php5-fpm.sock;
    }
    include /etc/nginx/sites-enabled/*;
}

If there was an error in somewhere, I would have tried to do something but here, I don't even know why this is not working. The only thing I tried was to restart both servers and that didn't help.

EDIT: Here is a single virtual server that this doesn't work with

server {
        listen 80;
        server_name example.com www.example.com;
        index index.php;
        root /var/www/example.com;
        location / {
                try_files $uri $uri/ /index.php?$args;
        }
        location ~ \.php$ {
                try_files $uri =404;
                fastcgi_split_path_info ^(.+\.php)(/.+)$;
                fastcgi_pass unix:/var/run/php5-fpm.sock;
                fastcgi_index index.php;
                include fastcgi_params;
        }

}

Directory and file permissions inside /var/www/example.com are root:www-data rwxr-xr-x

Also forgot to mention:

NGINX Version: 1.8.0
PHP version: 5.6.11-1~dotdeb+7.1 w/ Zeng Opcache v7.0.6-dev