Learn How to Downgrade Your Galaxy Note 8
If the Galaxy Note 8's Android Oreo update ruins your device performance or you can't stand the new user interface, you should be able to downgrade back to Nougat.
If you think this might be something you're interested in, we recommend getting familiar with the downgrade process before the Galaxy Note 8 Android Oreo release date. This way you're prepared.
Downgrading from Android Oreo to another version of Android will take time, particularly for those of you new to the downgrade process. In some cases, it could take several hours.
If you don't know how the downgrade process works on Samsung phones, this guide from XDA-Developers will help get you situated.