Added upgrade for 2.1.1 and updated version.
diff --git a/system/database/drivers/pdo/pdo_driver.php b/system/database/drivers/pdo/pdo_driver.php
index 5de2079..4fc65ae 100644
--- a/system/database/drivers/pdo/pdo_driver.php
+++ b/system/database/drivers/pdo/pdo_driver.php
@@ -9,7 +9,7 @@
  * @license		http://codeigniter.com/user_guide/license.html
  * @author		EllisLab Dev Team
  * @link		http://codeigniter.com
- * @since		Version 2.1.0
+ * @since		Version 2.1.1
  * @filesource
  */