The first Android-powered Blackberry smartphone, the Blackberry Priv came running on the Android Lollipop but Blackberry has since given the Priv its Marshmallow update.
The Marshmallow update was released for the unlock version in April this year. Since then AT&T Blackberry Priv users have been waiting for their Marshmallow update to arrive but that never happen until now.
AT&T is about 3 months late but at least it is here now. Not only will the Blackberry Priv users be able to enjoy the new Marshmallow OS but they will also be getting all the new features that come with the Marshmallow OS including the new Doze feature as well as the Google Now on Tap. The Blackberry Keyboard will also be updated at the same time.
The update will be available over-the-air. If you have not received your update notification, you can update it manually by going to Setting > Software Update.