Among other incremental improvements, the YouTube app version 4.3.9 includes integration with Google+. You can now use your Google+ profile when commenting or liking videos. Also, YouTube has fixed the “fullscreen button bug” which some might have experienced while switching across fullscreen mode.
Another feature is the TV playback controls directly available on the notification bar. This gives you easier access to YouTube playback even while switching across apps. This will come in very useful when you’re watching YouTube videos through a paired TV and you want to use another app.
As usual, you can update your YouTube app from Google Play right on your device, or you can initiate the update from your browser through Google Play on the web.
[via Android Authority]