WhatsApp will send or may have sent you an update requesting you agree to their new terms and condition. Try and read the terms and condition before agreeing.

When you agree, go to Settings > Accounts. You will see that option to allow sharing of your information on Facebook have been checked for you. You have just between now and September ending to change it (uncheck it) otherwise you will not be able to change it again. Please be on the alert and inform others. Its another attempt to start sharing your WhatsApp information on Facebook which you will not have control over anymore.

This is true, I have unchecked mine.

No one knows the source of Whatsapp and the information shared on Whatsapp is always encrypted. Once you agree or don’t uncheck, all your information will be shared on Facebook.

It’s an advice worth acting on.

Source: http://afrolad.com/stop-whatsapp-from-sharing-your-information-with-facebook/