Now, all the OnePlus phones from 5 to the 6T are running stable Android 9.0 Pie therefore, at this time it is the right moment to deal with a number of some small bugs and present latest features. As is the custom, the initial improvements are launched for the Open Beta participants. The complete list is here as to what new is coming with the OxygenOS Open Beta 12 for the OnePlus 6 and 6T and the Open Beta 26 for the OnePlus 5 and 5T.
The software changelogs for both of the versions are mostly similar – the OnePlus 5/5T is supposed to have support for quick replies in landscape mode (for instance, at times you are playing games or watching videos), optimizations for the screenshots and some further Gaming mode enhancements.
Users of the OnePlus 6/6T Open Beta further obtain the OnePlus Laboratory together with the Game mode improvements, screenshot optimization and the quick reply function. A further included feature is the support for world clock having weather information.
You can suppose these features are to come over the stable build in a coming update.