The new feature for WhatsApp in 2022 will use APIs in iOS 15. This is because the platform wants to add profile pictures to notifications in the Notification Center and the top-screen banners when a user receives a message.
This feature has been available on Android devices for some time. This latest update on the iOS platform is expected to bring equality across both platforms.
Though the update is available for beta testers only, it will be regulated to all the users once the changes get final. WhatsApp tests it first on beta users to check if there is any bug in the change.