Less than a month after WhatsApp introduced free voice calls with clients of its Android application, so the Facebook-owned organization has started rolling the feature out to its iOS clients.

Like the launch of calling on Android, which was initially spotted by enthusiastic clients in February, the feature won’t be available to all Apple device owners at once. The organization said it “is rolling out slowly throughout the following weeks” — that is faster than the Android deployment, but you’ll need some patience. (Unfortunately, I don’t appear to have the feature just yet, for what its worth.)

With 800 million monthly active clients on the WhatsApp service, this feature has the potential to upset a lot of carriers worldwide who have already seen their SMS incomes decimated by the rise of messaging applications. WhatsApp itself handles a larger number of messages from its clients than there are worldwide SMS sent every day. It’s worth noting, however, that we don’t know what number of are on the iOS application.

Today’s iOS application update also includes a couple of other nifty features, essentially support for the iOS 8 share extension which allows you to send videos, photographs and links to WhatsApp chats from other applications. Users can now also take photographs rapidly inside chats, and there’s a choice to send multiple videos at one time — as you can do with photographs — each of which can be cropped and rotated before being shared.

The launch of calling for iOS is the most recent in a steady stream of updates aimed at making WhatsApp more helpful than a mere free text message replacement. Another progression was the launch of a desktop web client in January, consequently enabling clients to keep in touch even when their smartphone is stowed away.

Yet, WhatsApp doesn’t include additional features, for example, business-consumer communication, payments or an platform, all of which are presently part of Facebook’s Messenger service. That doesn’t look like changing for some time, since those differences help Facebook’s messaging applications appeal to a range of groups of audiences — however it does make it difficult for WhatsApp to monetize its service in a meaningful way. For now, at least.