 
 @UIApplicationMain
 class AppDelegate: UIResponder, UIApplicationDelegate {
-    var window: UIWindow!
+    var window: UIWindow?
     var profile: Profile!
 
-    private let appVersion = NSBundle.mainBundle().objectForInfoDictionaryKey("CFBundleShortVersionString") as String
+    private let appVersion = NSBundle.mainBundle().objectForInfoDictionaryKey("CFBundleShortVersionString") as! String
 
     func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
         // Setup a web server that serves us static content. Do this early so that it is ready when the UI is presented.


        // Extract the WebKit version and use it as the Safari version.
        let webKitVersionRegex = NSRegularExpression(pattern: "AppleWebKit/([^ ]+) ", options: nil, error: nil)!
        let match = webKitVersionRegex.firstMatchInString(userAgent, options: nil, range: NSRange(location: 0, length: countElements(userAgent)))
        if match == nil {
            println("Error: Unable to determine WebKit version")
            return

        profile = BrowserProfile(localName: "profile")

        self.window = UIWindow(frame: UIScreen.mainScreen().bounds)
        self.window!.backgroundColor = UIColor.whiteColor()

        let controller = BrowserViewController()
        controller.profile = profile
        self.window!.rootViewController = controller
        self.window!.backgroundColor = UIColor(red: 0.21, green: 0.23, blue: 0.25, alpha: 1)
        self.window!.makeKeyAndVisible()

#if MOZ_CHANNEL_AURORA
        checkForAuroraUpdate()
