The not-so-widely-used trusted face smart unlock feature has officially been removed from Android. Android Police reported that the feature has been completely removed from devices running Android 10 or below.
The feature was added to Android in 2014 and existed alongside other smart unlock features that keep your device unlocked under certain circumstances. Examples include on-body detection, trusted places, trusted devices, and voice match. None of the other smart unlock features have been removed as of right now.
Removal of smart lock functionality can happen so seamlessly because it has never been a part of the Android firmware. It has always been controlled by Google Play Services, so a recent Play Services update probably removed the trusted face feature.
We don’t know if it’s just a temporary removal, but many people expected trusted face smart unlock to be deprecated since it was broken in the Android Q Beta 6. Also, Google has been working on its own face unlock feature, so it makes sense they wouldn’t want to maintain two different ways to use similar functionality.
Android Police verified that the feature has been removed from the OnePlus 6T, the Samsung Galaxy S9 and Galaxy S10, and the Nokia 3.2. This is also the case for every device we have tested it on thus far, including the first-generation Google Pixel running Android 10. But, if you really can’t live without the trusted face smart unlock feature, it appears to still be available in the latest Lineage OS 15.1 release, so I guess that’s always an option.