WhatsApp starts rolling out an update for its iPhone version. The update version comes with a single tap to switch between voice calls and video calls, the '@' button shows in group chats which allows to scroll back to unread messages. The Android beta app user already received the feature like the quick toggle for voice to video calls.
The update v2.18.22 is now available on the App Store. The feature works like just tap the video button while on a voice call, then a request will be sent to the recipient. By accepting the other user will convert the voice call into a video call instantly. It will work properly if both the users have the latest version of WhatsApp.