As you may have seen in the news, there has been a vulnerability discovered in the app.
More worryingly is that this vulnerability is being exploited to install spayware on your device and without the update, there's nothing you can do to stop it snooping on you via the camera, the microphone and it can even read your messages.
It can control your camera and microphone, scan your messages and collect location data.
WhatsApp is used by millions of people around the world and Facebook, the owners of WhatsApp are encouraging users to install the update.
Get the update from your app store of choice and check you have the latest version installed:
iOS : v2.19.51
It's always frustrating when you have to constantly update your apps, but when it's your privacy at stake, you know what you have to do.