The Galaxy Note 8 got updated with the January 2018 security patch not too long ago, and Samsung is now rolling out a new software update for its newest flagship. Oddly, the security patch is still on January, and there's nothing in the changelog other than “improved security.” It's possible the company has thrown in a few additional security fixes or has fixed some bugs that may have cropped up with the last update. The update is rolling out in Brazil and France at the moment, so it certainly doesn't look limited to a particular market.
Galaxy Note 8 gets new update
If there are new security fixes in there, they could be related to the Meltdown and Spectre processor exploits that have rocked the tech world. These exploits are more dangerous on actual PCs but do affect smartphones as well, so maybe that is what the new Note 8 update targets. There's no way to tell right now, but if you have a Note 8 and are in the aforementioned countries, you can check if the update is available in the Software update section of the settings. The firmware version on the new build is N950FXXU3BRA8.
Update: This update could indeed include the Meltdown and Spectre patches, as Verizon recently sent out an update to the Note 8 with those patches. Again, no proper changelog means nothing can be confirmed, but an update's an update, so go see if it's available for your Note 8!