meteor/tools/updater.js

// During automated QA of the updater, modify this file to set testingUpdater to
// true. This will make it act as if it is at version 0.1.0 and use test URLs
// for update checks.
var testingUpdater = false;

var fs = require("fs");
var http = require("http");
var https = require("https");
var path = require("path");
var semver = require("semver");
var Future = require('fibers/future');

var files = require(path.join(__dirname, 'files.js'));

var manifestUrl = testingUpdater
      ? 'https://s3.amazonaws.com/com.meteor.static/test/update/manifest.json'
      : 'https://update.meteor.com/manifest.json';

/**
 * Downloads the current manifest file and returns it via a callback (or
 * null on error)
 */
exports.getManifest = function () {
  return files.getUrl({url: manifestUrl, json: true});
};