diff --git a/includes/unicode.inc b/includes/unicode.inc
index 228981b..4c20245 100644
--- a/includes/unicode.inc
+++ b/includes/unicode.inc
@@ -272,17 +272,15 @@ function truncate_utf8($string, $len, $wordsafe = FALSE, $dots = FALSE) {
  * - Only encode strings that contain non-ASCII characters.
  * - We progressively cut-off a chunk with truncate_utf8(). This is to ensure
  *   each chunk starts and ends on a character boundary.
- * - Using \n as the chunk separator may cause problems on some systems and may
- *   have to be changed to \r\n or \r.
  */
 function mime_header_encode($string) {
   if (preg_match('/[^\x20-\x7E]/', $string)) {
-    $chunk_size = 47; // floor((75 - strlen("=?UTF-8?B??=")) * 0.75);
+    $chunk_size = 45; // floor((75 - strlen("=?UTF-8?B??=\r\n ")) * 0.75);
     $len = strlen($string);
     $output = '';
     while ($len > 0) {
       $chunk = drupal_truncate_bytes($string, $chunk_size);
-      $output .= ' =?UTF-8?B?'. base64_encode($chunk) ."?=\n";
+      $output .= ' =?UTF-8?B?'. base64_encode($chunk) ."?=\r\n ";
       $c = strlen($chunk);
       $string = substr($string, $c);
       $len -= $c;