As reported by TechDay last month, WhatsApp rolled out voice calling capabilities for its Android users, seriously upping its game in the instant messaging world.

While the announcement was well received and well reviewed by Android users, iPhone users were left in the cold with no similar launch for iOS.

However, iOS users can today jump on the WhatsApp VoIP bandwagon with the popular instant messaging app finally announcing the voice calling capability is now available on iOS as well as Android.

The WhatsApp Calling feature utilises local Wi-FI connections or data rather than a user's cellular plan's voice minutes or prepaid data for making calls, allowing users to get in touch with others completely free.

The calling feature has been added to an update on iTunes, the latest version to WhatsApp Messenger, 2.12.1, however the company says “WhatsApp Calling is rolling out slowly over the next several weeks”, so not all iOS users may be able to access the feature straight away.

The news further supports reports that WhatsApp is 'one of the most disruptive forces in the history of the telecommunications industry' by US business magazine, Forbes.

Last December, industry analysts Ovum noted that in the face of massive growth of messaging and VoIP apps, 2015 will see mobile operators continuing to fight to remain relevant in the mobile messaging and voice market.