https://www.theverge.com/circuitbreaker/2018/1/2/16840174/oneplus-5-face-unlock-oxygenos-open-beta

As promised, owners of the original OnePlus 5 can now unlock their phones via facial recognition with the new OxygenOS Open Beta 3 based on Android Oreo. As spotted by XDA, the Face Unlock feature will unlock your phone when you tap the device’s power button and point the camera at your face.

Face Unlock is a coveted feature on the newer OnePlus 5T, mostly for convenience because the feature isn’t as secure as a fingerprint or Apple’s Face ID tech (you can’t use it to authorize payments, for example). In our review of the 5T, my colleague Vlad noted that Face Unlock never gave a false positive by authenticating another person on his device. However, someone was able to unlock it simply by flashing the phone at Vlad’s face for a split second. Aside from facial recognition, the new beta release also includes an updated security patch, general bug fixes, and fixes for 5G Wi-Fi connection issues. There’s no word on when the final update will be rolled out, though XDA notes it could be in January.