Google started rolling out the April 2020 security patch for its Pixel devices from earlier today. The update primarily patches a number of security vulnerabilities and fixes some Bluetooth issues. On the Pixel 4 series, the update also adds a handy "Require Eyes to be Open" feature.
As previously detailed, this feature requires that Pixel 4 users keep their eyes open as the device would not unlock otherwise. When the Pixel 4 initially shipped, it was discovered that one could unlock the device even when the owner is not looking at the display or their eyes are not open. This was a major security lapse on Google's part especially since the Pixel 4 shipped with dedicated facial scanning hardware like the iPhone X/iPhone 11 series. Following all the criticism it received, Google promised back in October to fix the issue in a future update.
The good thing is that Google has not only introduced the "Require Eyes to be Open" feature with the April 2020 security update, but it has also enabled the feature by default. Once you install the April 2020 security patch on your Pixel 4 or Pixel 4 XL and go to Settings -> Security -> Face Unlock, you will notice that the feature is already enabled.