Index: program/lib/Mail/mimePart.php
===================================================================
--- program/lib/Mail/mimePart.php	(revision e8a1b7ef8f7135a1c89f6d75fc30aefb1f3b1a22)
+++ program/lib/Mail/mimePart.php	(revision 5ec762a0850af60f8edd3d90abbf4aa9e4ae4d8c)
@@ -398,5 +398,5 @@
 	// value needs encoding if contains non-ASCII chars or is longer than 78 chars
 
-        if (preg_match('#[\x20-\x7E]#', $value)) { // ASCII
+        if (!preg_match('#[^\x20-\x7E]#', $value)) { // ASCII
 	    $quoted = addcslashes($value, '\\"');
 	    if (strlen($name) + strlen($quoted) + 6 <= $maxLength)