code: function getAvailableUpdates() {
          var result = [];
          Object.keys(extensions).forEach(function (extensionId) {
              var extensionInfo = extensions[extensionId];
              // skip extensions that are not installed or are not in the registry
              if (!extensionInfo.installInfo || !extensionInfo.registryInfo) {
                  return;
              }
              if (extensionInfo.registryInfo.updateCompatible) {
                  result.push({
                      id: extensionId,
                      installVersion: extensionInfo.installInfo.metadata.version,
                      registryVersion: extensionInfo.registryInfo.lastCompatibleVersion
                  });
              }
          });
          return result;
      }
docs: Gets an array of extensions that are currently installed and can be updated to a new version
  @return {Array.<{id: string, installVersion: string, registryVersion: string}>}
  where id = extensionId
  installVersion = currently installed version of extension
  registryVersion = latest version compatible with current Brackets