Upgrading Codeigniter from 1.7.3 to 2.2.2 - Issue with sessions library

[eluser]adela[/eluser]
So,

Code:

$this->session->sess_destroy();

was used previously in 1.7.3 version probably because there was bug on it and it didn't work correctly, that's right? I believe there was no error on it because of that bug.

Also, is this code below correct in that case as you said?: unset_userdata() will do the similiar job as sess_destroy()

Code:

function login_do()
{
    if ( $_POST['username'] && $_POST['password'] )
    {
        $user = $this->db->where( array( 'users_name' => trim( $_POST['username'] ), 'users_password' => sha1( md5( $_POST['password'] ) ) ) )->get( 'users' );
        if ( $user->num_rows == '1' )
        {
            $user = $user->row();
            $data = array( 'logged' => true, 'users_id' => $user->users_id );
            if ( $user->users_teams_id > '0' )
            {
                $leader = $this->db->where( array( 'team_leader_id' => $user->users_id, 'teams_id' => $user->users_teams_id ) )->get( 'teams' )->row();
                $data['teams_id'] = $user->users_teams_id;
                if ( $leader )
                    $data['leader_teams_id'] = $user->users_teams_id;
            }

            $this->session->unset_userdata( array( 'logged' => false, 'users_id' => false, 'teams_id' => false, 'leader_teams_id' => false ) );
            $this->session->set_userdata( $data );
        }
        else
            $this->session->set_flashdata( 'error', 'user_pass' );
    }
    else
        $this->session->set_flashdata( 'error', 'data' );

    redirect( 'home' );
}