Unable to Load the app with ionic-angular2.0.0-beta.7

Hello, When I updated from ionic-angular2.0.0-beta.6 to 2.0.0-beta.7. I get this error : Cannot read property ‘registerBackButtonAction’ of undefined in app.js(line:31) on browser. i.e on node_modules/ionic-angular/components/app/app.js

I followed the steps given here: https://github.com/driftyco/ionic/blob/2.0/CHANGELOG.md#angular-update-to-200-rc1
Here is my package.json file:

{
  "dependencies": {
    "@angular/common": "^2.0.0-rc.2",
    "@angular/compiler": "^2.0.0-rc.2",
    "@angular/core": "^2.0.0-rc.2",
    "@angular/http": "^2.0.0-rc.2",
    "@angular/platform-browser": "^2.0.0-rc.2",
    "@angular/platform-browser-dynamic": "^2.0.0-rc.2",
    "@angular/router": "^3.0.0-alpha.6",
    "es6-shim": "^0.35.0",
    "ionic-angular": "^2.0.0-beta.7",
    "ionic-native": "^1.1.0",
    "ionicons": "3.0.0",
    "reflect-metadata": "^0.1.2",
    "rxjs": "^5.0.0-beta.6",
    "zone.js": "^0.6.12"
  },
  "devDependencies": {
    "del": "2.2.0",
    "gulp": "3.9.1",
    "gulp-watch": "4.3.5",
    "ionic-gulp-browserify-typescript": "^1.1.0",
    "ionic-gulp-fonts-copy": "^1.0.0",
    "ionic-gulp-html-copy": "^1.0.0",
    "ionic-gulp-sass-build": "^1.0.0",
    "ionic-gulp-scripts-copy": "^2.0.0",
    "run-sequence": "1.1.5"
  },
  "cordovaPlugins": [
    "cordova-plugin-device",
    "cordova-plugin-console",
    "cordova-plugin-whitelist",
    "cordova-plugin-splashscreen",
    "cordova-plugin-statusbar",
    "ionic-plugin-keyboard"
  ],
  "cordovaPlatforms": [
    "ios",
    {
      "platform": "ios",
      "version": "",
      "locator": "ios"
    },
    "android"
  ],
  "name": "nanobi-analytics",
  "description": "Nanobi Analytics: An Ionic project"
}

My Current ionic version is: 2.0.0-beta.30