Bug 387860 – Subject lines in mails may contain mangled multi-byte characters.

Bugzilla/Mailer.pm

@@ -66,6 +66,7 @@ sub MessageToMTA {
     # Encode the headers correctly in quoted-printable
     foreach my $header qw(From To Cc Reply-To Sender Errors-To Subject) {
         if (my $value = $email->header($header)) {
+            $value = Encode::decode("UTF-8", $value) if Bugzilla->params->{'utf8'};
             my $encoded = encode('MIME-Q', $value);
             $email->header_set($header, $encoded);
         }