--- lib/ezutils/classes/ezsendmailtransport.php	2011-11-29 12:21:10.248767400 +0100
+++ extension/globaloverrides/classes/kerneloverrides/ezsendmailtransport.php	2012-02-14 17:24:58.287108000 +0100
@@ -64,8 +64,10 @@
             // However, we can use "undisclosed-recipients:;" in $to.
             if ( $sys->osType() != 'win32' )
             {
-                $excludeHeaders[] = 'To';
-                $receiverEmailText = count( $mail->ReceiverElements ) > 0 ? $mail->receiverEmailText() : 'undisclosed-recipients:;';
+				$excludeHeaders[] = 'To';
+				$insertUndisclosedRecipient = $ini->variable( 'MailSettings', 'SendmailInsertUndisclosedRecipient' );
+				$recipientText = $insertUndisclosedRecipient == 'enabled' ? 'undisclosed-recipients:;' : '';
+				$receiverEmailText = count( $mail->ReceiverElements ) > 0 ? $mail->receiverEmailText() : $recipientText;
             }
             // If Windows PHP mail() implementation, we can specify a To: header in the $additional_headers parameter,
             // it will be used as the only To: header.