diff --git email_example/email_example.module email_example/email_example.module
index 630f039..8cc2e1a 100644
--- email_example/email_example.module
+++ email_example/email_example.module
@@ -122,7 +122,13 @@ function email_example_mail_alter(&$message) {
   // For the purpose of this example, modify all the outgoing messages and
   // attach a site signature. The signature will be translated to the language
   // in which message was built.
-  $message['body'][] = t("--\nMail altered by email_example module.", array(), $message['language']->language);
+
+  $signature = t("\n--\nMail altered by email_example module.", array(), $message['language']->language);
+  if (is_array($message['body'])) {
+    $message['body'][] = $signature;
+  } else {  // Some modules use the body as a string, erroneously.
+    $message['body'] .= $signature;
+  }
 }
 
 ///// Supporting functions ////