Trying to sign in during the maintenance will result in a site maintenance notification page, but anyone already logged in should be able to stay online but will be unable to... (brutalgamer.com)
Most exciting is probably the new Notifications page, which now lists all the recent alerts that have come in from your iOS or Android device for you to scroll through, even if you previously dismissed them. (slashgear.com)
It's a shortcut to the app notification page, which you'll also find listed at Settings > Sound & notification > App notifications. (goodereader.com)