Here is the latest OxygenOs Open Beta 3 build for OnePlus 6T
Updated Android security patch to 2019.1
Messages now support landscape mode
Deep integration with Google Duo
Added more search options to improve the accuracy of search results
Weather descriptions more accurate
Added more unit options for precipitation, visibility, pressure and other data
Added more detailed descriptions to weather icons
How to upgrade system?
Download the software build for your device on this page. Please back up your data before flashing your device.Plug your phone into your computer and copy the downloaded .zip to your phone’s storage. If you’re using a Mac, you can install Android File Transfer for this operation.After the .zip file is copied to your phone, go to ‘Settings’ – ‘system update’, click the ‘settings’ icon on the top right corner, choose ‘Local upgrade’, find the .zip file and click on ‘Install’ to confirm.The update takes about a minute (depending upon the file size), once done reboot your device to boot into the latest Oxygen OS.