OnePlus is rolling OxygenOS 10.3.0 for the 6 and 6T which comes with November 2019 Android security patch. It also fixes a few issues and improves camera performance.
The new build also brings back the notch area hiding option which can be found under the Settings > Display > Notch display menu.
Here’s the complete changelog of OxygenOS 10.3.0 for OnePlus 6/6T: