Facebook-owned messaging app WhatsApp has been updated for iOS users, bringing the long-awaited voice calling feature.
Following the roll out for Android devices last month, WhatsApp users on iPhones and iPad can now make calls to pals directly from the app.
The Wi-Fi-only feature will be a boon to those seeking to avoid international calling rates while keeping in touch with friends and family.
The update comes as WhatsApp revealed a 100 million growth in monthly active users in the last three months alone.
Co-founder Jan Koum says there are now 800m active users, compared to the 700m the firm has racked up by January.
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Part of the growth can probably be attributed to the in-app calling introduced for Android users.
Now the feature has been opened up to iOS users the company can probably expect another huge influx of monthly active users.
If WhatsApp continues growth at the at the current rate, it may hit 1 billion active users by the end of the year.