code: function initiateUpdateProcess(formattedInstallerPath, formattedLogFilePath, installStatusFilePath) {
  
          // Get additional update parameters on Mac : installDir, appName, and updateDir
          function getAdditionalParams() {
              var retval = {};
              var installDir = FileUtils.getNativeBracketsDirectoryPath();
  
              if (installDir) {
                  var appPath = installDir.split("/Contents/www")[0];
                  installDir = appPath.substr(0, appPath.lastIndexOf('/'));
                  var appName = appPath.substr(appPath.lastIndexOf('/') + 1);
  
                  retval = {
                      installDir: installDir,
                      appName: appName,
                      updateDir: updateDir
                  };
              }
              return retval;
          }
  
          // Update function, to carry out app update
          var updateFn = function () {
              var infoObj = {
                  installerPath: formattedInstallerPath,
                  logFilePath: formattedLogFilePath,
                  installStatusFilePath: installStatusFilePath
              };
  
              if (brackets.platform === "mac") {
                  var additionalParams = getAdditionalParams(),
                      key;
  
                  for (key in additionalParams) {
                      if (additionalParams.hasOwnProperty(key)) {
                          infoObj[key] = additionalParams[key];
                      }
                  }
              }
  
              // Set update parameters for app update
              if (brackets.app.setUpdateParams) {
                  brackets.app.setUpdateParams(JSON.stringify(infoObj), function (err) {
                      if (err) {
                          resetStateInFailure("AutoUpdate : Update parameters could not be set for the installer. Error encountered: " + err);
                      } else {
                          setAppQuitHandler();
                          CommandManager.execute(Commands.FILE_QUIT);
                      }
                  });
              } else {
                  resetStateInFailure("AutoUpdate : setUpdateParams could not be found in shell");
              }
          };
          setUpdateStateInJSON('updateInitiatedInPrevSession', true)
              .done(updateFn);
      }
docs: Initiates the update process, when user clicks UpdateNow in the update popup
  @param {string} formattedInstallerPath - formatted path to the latest installer
  @param {string} formattedLogFilePath  - formatted path to the installer log file
  @param {string} installStatusFilePath  -  path to the install status log file