Although this update comes just in time to offer Nougat, OnePlus decided to use Android Marshmallow as foundation for a new firmware once again. The highlight of OxygenOS 3.2.8 is the 1080p@60 fps video recording capability.
http://www.notebookcheck.net/OnePlus-3-gets-OxygenOS-3-2-8.185567.0.html