WhatsApp is continuing its apparent mission to kill traditional voice calls.

Traditionally voice calls have long been restricted to your network connection, but with voice-over-internet calling (also called VoIP calling), messenger apps like WhatsApp can turn a standard Wi-Fi connection into a way to place free calls. Facebook-owned WhatsApp starting letting Android users take advantage of VoIP calling a few weeks ago, and now it is rolling out the feature to iOS users.

The feature, which has been branded as WhatsApp Calling, is described as a means of phoning your friends and family for free, even if they live in a different country. WhatsApp uses your phone’s internet connection instead of your cellular plan’s voice minutes, though data charges through your carrier may be applied. WhatsApp Calling will roll out to iOS users over the next several weeks.

VoIP calling isn't a new thing entirely, as Skype already offers it, for example. The VoIP calls are also of a higher quality than normal voice calls, or at least it sounded that way when we tested the feature in WhatsApp for Android last month. That said, many have assumed WhatsApp's adoption of the feature will likely make a big impact on the number of calls made over networks.

It'll therefore be interesting to see how carriers and their plans change over time as a result of more and more apps utilising VoIP.

READ: WhatsApp voice voice over internet calling arrives for Android