enyo.kind({
  name: "WebLetter.Config",
  published: {
    serverUrl: "http://localhost/webletter/server/letter.php",
    method: "post",
    debugging: true
  }
});

enyo.kind({
  name: "WebLetter.Config",
  published: {
    serverUrl: "http://localhost/webletter/server/letter.php",
    method: "post",
    debugging: false
  }
});

change debbuging value to false