First, you will notice that it runs Android 6.0.1 Marshmallow. There is no Nougat yet because Google has not officially launched it.
Samsung has revamped its Settings UI to make it simpler with sub-menus hidden.
Iris scanner option is found in Security settings which requires use of a physical IRIS scanner. Based on the information provided by the ported ROM, it seems that IRIS scanner uses LEDs and perhaps there may be a secondary camera dedicated to scanning IRIS.
But you can clearly see that IRIS scanner is a brand, new feature on the Galaxy Note 7.
There’s also new S Bike mode, probably short for “Sports Bike” mode. This mode gives you only the most important notifications and ignores others.
The Quick Settings Panel has gotten cleaner with option to open easily.
There is a new “UHQ upscaler”, an advanced equalizer for your headphones. We don’t know if this actually requires the new DAC hardware on Note 7 but it’s a hint that Note 7 may come with a powerful DAC.
The new Air Command now has default options for Note, Smart Select, Screen Write, and Translate.
The new Note app has changed drastically along with option to add your voice, images, and more.