WhatsApp Calling is now enabled for all
Most of them who were asking their friends to help on enabling Voice calling feature on WhatsApp can breathe easy. Seems like the latest update has enabled Voice Calling feature for Android users.
Though this feature is yet to be rolled out to iOS or Windows Phone users, they might get it eventually. This feature should be enabled if you are running WhatsApp version 2.12.5 or above. The latest being version 2.12.19 which is yet to be rolled out. The latest version of WhatsApp might reach you in the next few days.