Removed cache-control header

src/download.php

@@ -105,7 +105,6 @@
 
    header("Pragma: ");
    header("Content-Description: SquirrelMail Attachment");
-   header("Cache-Control: no-cache, must-revalidate");
    if ($absolute_dl == "true") {
       switch($type0) {
          case "text":