- If you haven’t used Face ID in 48 hours, or if you’ve just rebooted, it will ask for a passcode.
- If there are 5 failed attempts to Face ID, it will default back to passcode. (Federighi has confirmed that this is what happened in the demo onstage when he was asked for a passcode — it tried to read the people setting the phones up on the podium.)
- Developers do not have access to raw sensor data from the Face ID array. Instead, they’re given a depth map they can use for applications like the Snap face filters shown onstage. This can also be used in ARKit applications.
- You’ll also get a passcode request if you haven’t unlocked the phone using a passcode or at all in 6.5 days and if Face ID hasn’t unlocked it in 4 hours.
Lots of people in the threads here yesterday seemed to misunderstand how these things are implemented. Importantly, you cannot set up FaceID without first setting up a password (biometrics are a carrot for getting users to set up passwords, not intended to subsume passwords), and you'll still be prompted for a passcode around once a week so you won't go forgetting it.