xss_clean in CI 3

to answer concisely and effectively : $config['global_xss_filtering'] = TRUE is deprecated and just to assure interdependence between versions of CI.
Instead Use :
- $this->security->xss_clean($data) ; // on each data. NO need to load the class Security
// you can see $this->input->post($v, TRUE) or $this->input->get('some_data', TRUE);
// (http://www.codeigniter.com/userguide3/li...-filtering)
- or xss_clean($data) and before load security helper for using this function

have a good day.