How to use WhatsApp or VOIP account via the IOS phone app ?

[iMore Question]

"VoIP is no longer going to take a backseat, as a WhatsApp call, for example, can be answered right from the lockscreen, just like a normal incoming call. They'll also be part of your recent and favorites lists."

 

[Tartarus]

We will have to wait till the official release of iOS 10 in September.

I'm on the Dev beta and WhatsApp calls still come in their app.

Developers are not allowed to push updates for iOS betas.