If you own an iPhone X or greater, you can use Face ID to unlock WhatsApp while iPhone 8 and lower devices will make use of Touch ID. Of course, if you're using WhatsApp quite often, the additional security protection added in the latest update may be bothersome, but better safe than sorry.
Hopefully this is an added layer of security that more messaging and social media apps will implement in the future.
WhatsApp for iOS has been updated to include support for Touch ID or Face ID to unlock the app. You can't lock select chats within the app yet but even an app-wide lock method is a useful feature.
To enable the feature, simply go to Settings Account Privacy and enable Screen Lock. Your WhatsApp notifications are still visible, and you can do quick replies within iOS without authentication.
It is worth noting the user is still able to read new WhatsApp notifications from their home screen with the tool switched-on, assuming they have such a feature enabled in the first place.
WhatsApp hasn't given a date for when a similar feature will arrive for Android, but it says it's on the way. This means iPhone users can now choose to set up Face ID or Touch ID to open the WhatsApp app on their device. From there, all you have to do is enable Screen Lock.