OnePlus introduced the Always-On Display feature with Android 11-based OxygenOS 11, which comes pre-installed on the OnePlus 8T. T-Mobile’s 8T (aka 8T+ 5G) was an exception as it didn’t have it out of the box, but it is now receiving the OxygenOS 126.96.36.199.KB09CB update that enables the feature.
The new firmware also includes October 2020 Android security patch and optimizes the battery performance. Additionally, it squashes bugs that caused software freezing and device overheating while also fixing a Bluetooth audio issue.
The update requires a 320MB download and is rolling out over the air. You should receive it on your unit any moment now if you haven’t already.