http://www.techradar.com/news/face-unlock-is-coming-to-the-oneplus-5

Start talking about the differences between the OnePlus 5 and the OnePlus 5T, and one of the major ones is the way you can use your face to unlock your phone on the newer handset. Now OnePlus has announced the older phone is getting the same feature too.

"Due to popular demand, Face Unlock is coming for the OnePlus 5," tweeted out OnePlus chief Carl Pei on Christmas Eve. "Thanks for the feedback, and merry Christmas!"