This isn't strictly an update to the WhatsApp app, but it could affect how you interact with it. You can now use a Google Now voice command to send a WhatsApp message to one of your contacts, just say "Ok Google, send a WhatsApp message to [contact name]." You will then be prompted to dictate the message you want to send.
Alternatively, you can record it all in one statement, like "Ok, Google, send WhatsApp message to Malcolm, I'm still in love with you," or something else.
If you're new to Google Now voice commands, hit the link to see a list of what else can be achieved with Google's handy personal assistant.