https://wccftech.com/oneplus-5-5t-get-gaming-mode-portrait-mode-in-front-camera-and-more/

While Android P is still yet to make it to the OnePlus 5 and 5T, the devices continue to get regular updates and new features. Both devices have an excellent open beta program and version 17/15 brings a significant number of changes to the system. It includes Gaming Mode 3.0 and a number of other system change. Most notably it comes with a front-facing portrait mode, just like on the OnePlus 6. The full changelog is as follows:\

The Toast message source is incredibly useful for finding applications that send out a lot of spam. Gaming Mode 3.0 adds a call suspend notification, text notification mode, and UI optimization. OnePlus’ suite of applications have gotten a facelift as well. The Notes app has been updated to be consistent with the system’s new UI along with the OnePlus Switch app. Other apps such as the included OnePlus Weather app get hourly weather forecasts. Lastly, the update bumps up the Android security patch of the devices to August. The update should be available OTA to all beta testers. Alternatively, the images can also be sideloaded via the OnePlus website.