Although OnePlus has yet to officially announce it, a new Open Beta build is now going out to the OnePlus 6 and OnePlus 6T. This arrives over-the-air for those who were already running the previous experimental build, as Open Beta 25 for the OnePlus 6 and Open Beta 17 for the OnePlus 6T. As you can see from the screenshot to the left, the sole purpose of this beta release, aside from bringing some unnamed optimizations for system performance, is to prepare the two phones for "major upcoming updates". Clearly that refers to Android 10. A few hours ago OnePlus outed the first beta...
Source: https://www.gsmarena.com/newest_open_beta_for_the_oneplus_6_and_6t_prepares_them_for_the_android_10_update-news-39013.php
