The company starts rolling out the OxygenOS 5.1.9 OTA for the OnePlus 6, which weighs around 342MB. If you have not received the OTA notification, you can use Oxygen Updater app or use any VPN app and set the region to Canada or Germany to get the OTA update early.

You can also download latest OxygenOS 5.1.9 full OTA update (link below) and flash it manually. Read on to know how to install the update manually on your OnePlus 6. OxygenOS 5.1.9 Changelog:

How to Install OxygenOS 5.1.9 Update for the OnePlus 6

  1. Download OxygenOS 5.1.9 zip file [HERE] and place it on internal storage of your device – Updated Android security patch to 2018.7 – Fixed issues with accidental touches triggering gestures ( Draw V) – Supported Telia Finland VoLTE (Default On) and VoWifi (Default Off) – General bug fixes and improvements Camera – Improved image quality – Integrated Google Lens mode – Added beauty mode for Selfie Portrait Messages – Added Group MMS Wireless & networks – Optimized stability for Wi-Fi connection – Fixed stability issue with the Bluetooth connection for cars
  2. Reboot the phone into stock Recovery (press Power + Volume Down buttons after switching off the phone)
  3. In recovery, wipe Cache
  4. Now, choose “Install from internal storage”, find your .zip file and flash it
  5. Your device will reboot automatically after installing the OS. [source]