Google had launched YouTube Music Key in November last year with very long name compared to competitors like Spotify, Rdio or Apple Music.
Recently Google has declared that it is changing it to ‘YouTube Red’ providing subscription service.
The new features are only that it show up a notification globe when you leave a video playing in the background as you switch to another app, or as a pop-up when you try to re-open YouTube later.
Google has just launched Marshmallow with new Nexus 5X which have amazing features and in which Youtube red will be included. If you want to use it than you have to update youtube app with new.
Google 