Check for null

application/models/User_model.php

@@ -93,7 +93,7 @@ class User_Model extends CI_Model {
 		$query = $this->db->get($this->config->item('auth_table'));
 
 		$ret = $query->row();
-		if ($ret->user_email != '') {
+		if ($ret->user_email ?? '' != '') {
 			return $ret->user_email;
 		} else {
 			return '';