Step-1: Install the WhatsApp apk from their site
Step-2: Navigate to data/data/com.whatsapp/shred_prefs/com.whatsapp_preferences.xml
Note: Root files access needed to be enabled.
Step-4: Go to Settings/Apps/Whatsapp and force stop it
Step-5: Start WhatsApp again
Note: WhatsApp call servers are down, so while you get the feature you need to wait for them to be up to actually use it