This size is available for both Android and iOS. On Android from version 219.221 and on iOS from version 2.19.20
So now we can block access to the application by fingerprint and on iOS-enabled devices also by facial recognition.
To access a user's chats it will be necessary to unlock the mobile and then the app.
Whatsapp becomes a much more secure application by implementing this measure, making the entire authentication process managed by the smartphone's operating system and consequently no data is sent to the company's servers.
To activate this new security measure, go to Whatsapp, go to Settings > Account > Privacy and then click on "Fingerprint Lock". There you will be able to configure how often the application will ask you to unblock your fingerprint.