This is a pretty good article explaining what was changed.
Samsung Galaxy Note 7 software update: More than just a green battery icon | ZDNet
The day after picking up my coral blue Note 7 from T-Mobile, a 404.67MB update appeared. We heard that this update was designed to change the battery icon from white to green so that it was clear to people that this was not a Note 7 with a faulty battery.
It turns out that Samsung included more goodies in the software update that add some value to your Note 7 experience.
Here is what the change log identifies:
User interface adjustments (Messages, Home screen, Quick panel,...)
Improved fingerprint recognition process
Overall device performance has been improved
The security of your device has been improved
A software update can include, but is not limited to: device stability improvements, new and/or enhanced features, and further improvements to performance.
USER INTERFACE ADJUSTMENTS
note-7-sw-update-1.jpg
Three screen resolution options exist for you to choose.
While not specifically identified in the change log, I found that Samsung pulled the screen resolution setting option out from being hidden deep in the battery power saving modes. You can now simply go to Settings>Display>Screen resolution. Three options exist for you to choose, and by using a lower resolution, you will see some amount of extended battery life. The options include HD (1280x720), FHD (1920x1080), and WQHD (2560x1440). I switched to FHD and honestly cannot tell a difference between it and WQHD. Previously, the battery mode informed me I would extend my battery life 45 minutes using this change.
As I previously wrote, much of what you can find in Android Nougat can be found on the Samsung Galaxy Note 7. One aspect of Nougat is the ability for an Android device to function like an iPhone with 3D (aka Force) Touch. This software update lets you press and hold on an app icon or folder on a home screen panel to initiate a pop-up with a couple options.
note-7-sw-update-2.jpg
This software update lets you press and hold on an app icon or folder on a home screen panel to initiate a pop-up with a couple options.
On an app shortcut, options include put to sleep, uninstall, and app info. This works for app shortcuts on the home screen or within folders. On a folder, an option to add apps to the folder appears. While these are very limited actions, the potential for developers to enhance actions may be possible.
The notification shade also changed a bit to where you will now see the words 'Block Notifications' appear to the left of 'Clear All' at the bottom of the shade. Tapping Block Notifications will then let you quickly toggle off notifications for the apps that are currently shown in your notification shade. This capability to manage your specific app notifications is also buried in settings, but this update brings them up for easier user access and use.
FINGERPRINT SCANNER PERFORMANCE
The Galaxy S7 fingerprint scanner was impressive with my previous Note 7, as they performed similarly. With this update, I swear the recognition is even faster and performance has been flawless.
SEPTEMBER ANDROID SECURITY UPDATE
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Prior to the Galaxy S7, Samsung did not have a great history of timely software updates. It committed to the monthly Android security program, and I've been impressed by the speed of these monthly updates. No other manufacturer has issued these updates faster than Samsung, and this software update includes the September security update.
OTHER EXPERIENCES
MORE SAMSUNG GALAXY NOTE 7
Verizon releases software update with warning, new battery indicator
Samsung says China explosions caused by 'external heating'
Samsung starts exchange program in the UK and Ireland
FAA: Powering on Galaxy Note 7 during flight prohibited
US govt recalls 1 million Note 7 phones
To make sure I have the best Note 7 experience, I did not restore anything, so I had to install about 50 apps and setup the new Note 7 from scratch. Previously, my Note 7 heated up as I performed this setup with it plugged into a fast charger. This time, I never noticed any warmth at all, and in my experiences after a day and a half, the Note 7 appears to run cooler.
So far, I have not noticed any lag or performance issues as I had previously experienced. I think some of those previous experiences may have been due to restoring the Note 7 from my S7 Edge, but I hope to continue to experience a flawless device with this new Note 7.
If you found other improvements or features in this software update, please share them with the rest of us in the comments.
IMPACTS OF UPDATE ON OLDER NOTE 7 UNITS
If you haven't yet replaced your Note 7, then this update will limit your charging to 60 percent and also have a pop-up appear that instructs you to shut down your phone and replace it every time you charge your Note 7. Please go visit your local carrier store and get it replaced as soon as possible. Samsung already shipped 500,000 units to stores in the US, so there should be supply available to replace your device.