OnePlus 6 and OnePlus 6T receiving OxygenOS 9.0.12/9.0.4 with January 2019 security patches OnePlus custom Android UI, namely OxygenOS, can be summed up as stock Android with wings. It has helped OnePlus and its performance-oriented persona surge higher, especially in markets like India where the mid-range dominates the sales trends. With all eyes on the ball, OnePlus has actively been updating its two flagships of 2018 with new OxygenOS features almost every month, and the newest update is already hitting both the OnePlus 6T and OnePlus 6 via OTA
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Preference:
-https://9to5google.com/2019/02/12/oxygenos-ota-oneplus-6t-oneplus-6/

Source: https://www.youtube.com/watch?v=SH8b2n2Hdkg