@ -397,7 +397,7 @@ class Mail_mimePart {
// RFC 2183/2184/2822:
// 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 <= $maxLength)
return " {$name}=\"{$quoted}\"; ";