diff --git a/system/core/Common.php b/system/core/Common.php
index 85e18e4..d66649f 100644
--- a/system/core/Common.php
+++ b/system/core/Common.php
@@ -716,8 +716,8 @@
 		// carriage return (dec 13) and horizontal tab (dec 09)
 		if ($url_encoded)
 		{
-			$non_displayables[] = '/%0[0-8bcef]/';	// url encoded 00-08, 11, 12, 14, 15
-			$non_displayables[] = '/%1[0-9a-f]/';	// url encoded 16-31
+			$non_displayables[] = '/%0[0-8bcef]/i';	// url encoded 00-08, 11, 12, 14, 15
+			$non_displayables[] = '/%1[0-9a-f]/i';	// url encoded 16-31
 		}
 
 		$non_displayables[] = '/[\x00-\x08\x0B\x0C\x0E-\x1F\x7F]+/S';	// 00-08, 11, 12, 14-31, 127