OnePlus is bringing more features from its flagship OnePlus 7 Pro to its older devices. The latest OxygenOS Open Beta brings DC dimming to the OnePlus 6 and 6T alongside more utility to the screen recorder and weather apps and the July security patch.
In order to get the latest features, you'll have to flash the beta firmware from OnePlus' site. If you've done this before, you'll get the new beta as an OTA update. The beta updates come in at about 275MB.
Source
Author: Michail
Source: GSMArena
OnePlus Android Firmware Updates