Hi. Do you get a button or and option to update the app upon getting this message. If yes, then clicking it to be redirected to the whatsapp.com site for a download. If you do get this option, try clicking your option and see if you do not have the update option there. And alternatively, if the Whatsapp messenger continues to work in-spite of the update message, you can just continue to ignore the message until it will nolonger let you use the app. At that stage, you should either have the update option button or you can try the suggestion provided by the Admin.
