The version of WhatsApp for iOS containing the video calling feature is supposedly 22.214.171.124. Considering that the version already in the App Store is 2.12.12, the next update to WhatsApp for iOS users might contain this new capability.
WhatsApp is also adding multiple chat tabs. Using these tabs, you can switch back and forth between individual chats without having to go back to the WhatsApp chats list. In addition, the app is getting a makeover with a focus on the color green.
Hopefully, adding video calling to WhatsApp doesn't take as long as adding VoIP did. After what seemed like an eternity, voice calling was added to the iOS variant of the app this past April.
Video calling is coming to WhatsApp
1. Notification of a video call
2. Users will have a movable preview box, be able to swap cameras and mute the microphone
source: Macerkopf.de (translated) via IBTimes