OnePlus may be slow to update many of its phones to the new version of Android, but the company is still doing the right thing (usually) to make security fixes. The OnePlus 6 and 6T are currently three years old, but security updates are underway for both phones, and now the November 2021 patches have arrived.
OxygenOS 11.1.2.2 is now available on the OnePlus 6 and 6T. The change log only mentions “improved system stability” and the November 2021 security patch level, with no other changes apparently. This is OxygenOS 11.1.1.1, the first update for both phones since September 2021, which brought patches and various bug fixes.

Credit: cooldeepak
This may be the latest official update for both the OnePlus 6 and 6T, as they promise only two years of Android updates and three years of security fixes. By 2021, both phones will still be strong enough, and the OnePlus will unlock the bootloader and make it easy to install custom ROMs, so if you’re interested in keeping your OnePlus 6 or 6T, visit the forum for each device (link below). updated.
OnePlus 6 forum ||| OnePlus 6T forums
OnePlus is still phasing out OxygenOS 11.1.2.2 to OP6 / 6T, but if you don’t want to wait, we have all the links we need (thanks to XDA member some_random_username). As usual for a OnePlus phone, all you have to do is download the correct package from the link below and move it to the phone’s main memory directory. Then go there Settings> System> System Update> Local Update Select the downloaded file and start the installation.