At the time of acquisition, Whatsapp had 450 million active users. The fact that the number has increased to 1.2 billion is indeed a proof of its constant innovations.
This feature is a result of Apple opening up Siri’s software to third party developers at its annual Worldwide Developers Conference last year.
Version 2.7.2 brings this feature to all the iOS devices running at least iOS 10.3. iOS 10.3 update has been released just a few months ago. It improved the overall security of the device.
You can activate this feature in Whatsapp’s settings menu and request Siri to read the latest messages using the usual “Hey Siri” command.