Codeigniter duplicate session issue

For one I would refactor your code and move a lot of it to a library.

You did not show your logout method, so this would be the way to do it.

PHP Code:

// unset one session item
$this->session->unset_userdata('some_name');

// unset multiple session items
$array_items = array(
    'username',
    'firstname',
    'lastname',
    'phone',
    'email',
    'centre_id',
    'zone_id',
    'mygroup',
    'loggedin'
);

$this->session->unset_userdata($array_items);

// destroy the session should be the last called.
$this->session->sess_destroy(); 


Try that in your logout method and see if it will work.

Still the same problems