With Chrome version 50, notifications are getting a shot of steroids as they can now include notification data inside, with actionable options. This is part of the Push API and it allows for encrypted data to be shown to the user directly inside of a notification, without the end-client having to request it. The notification can also tell a user’s device whether it should make sound, vibrate or stay silent upon receiving it.Another big change perhaps is that from now on, new versions of Chrome no longer support older operating systems. Windows XP, Windows Vista and any version of Mac OS X older than Mavericks got cut off today, meaning they no longer receive feature nor security updates.
And now notifications also offer better analytics to the server telling it whether the user actively closed the notification and enabling cross-device notification dismissal.
More details Neowin.