Brian Acton, Co-founder WhatsApp, at a recent event confirmed that the voice calling feature will be rolled out to iOS users in "couple weeks".
Speaking Facebook's F8 developers' conference, Acton said that WhatsApp team "refined and iterated voice calling" last year before launching it on Android.
However, an exact date frame for the release of the voice calling feature on iOS was not revealed. When pressed later he said, "Well, several weeks."
WhatsApp voice calling feature is being rolled out in phases, which means it is currently available to limited users and invites only work within specific time periods. For this you need to download version 2.11.528 from the Play Store or version 2.11.531 from the WhatsApp website. Voice-calling ability can be activated by receiving a call from someone whose voice-calling is already activated.
The leaked WhatsApp for iPhone screenshots showed mute, message, and speaker options while in-call, with 'WhatsApp Call' clearly marked on the top left of the calling screen. Notably, the current WhatsApp version available to download from the App Store is 2.11.16, tipping that the voice calling feature might be rolled out with the next app update.