Zuckerberg initially promised independence, but plans are now underway to unify the underlying messaging infrastructure of WhatsApp, Instagram, and Facebook Messenger.
https://www.nytimes.com/2019/01/25/technology/facebook-instagram-whatsapp-messenger.html
.onion: https://www.nytimes3xbfgragh.onion/2019/01/25/technology/facebook-instagram-whatsapp-messenger.html