https://wccftech.com/oneplus-6-6t-5-and-5t-to-get-android-10-starting-this-month/

At the OnePlus 7T Pro reveal today, OnePlus shed some light on its Android 10 roadmap and gave us a rough idea about when each eligible device would get the update. As detailed in a report earlier, the OnePlus 6 and 6T were expected to receive it sometime last month. Today, we have confirmation that the rollout will start sometime this month. We don't know the exact date as there was none specified. Along with the standard Android 10 goodies, OxygenOS 10 also brings forth the following changes.

We don't know if there's an open beta scheduled for OnePlus 6 and 6T just yet, and if it is, we can expect it to drop sometime in the coming week. We'll be sure to keep you posted about any developments.