We can solve it by:

1. System/codeigniter/CodeIgniter.php

Change  : $objects[$class] =& new $name();

To : $objects[$class] =new $name();

2. System/database/DB.php

Change : $DB =& new $driver($params);

To : $DB =new $driver($params);

3. System/libraries/Loader.php

Change : $CI->dbutil =& new $class();

To : $CI->dbutil = new $class();

4. System/libraries/URI.php

Change : if ( ! preg_match(“|^[“.preg_quote($this->config->item(‘permitted_uri_chars’)).”]+$|i”, $str))

To : if ( ! preg_match(“|^[“.($this->config->item(‘permitted_uri_chars’)).”]+$|i”, rawurlencode($str)))

5. index.php

Change : error_reporting(E_ALL);

To : error_reporting(E_ALL & ~E_DEPRECATED);