Shortly after announcing a milestone 800 million monthly active users, WhatsApp today launched an iOS update that adds free voice calling.
"Call your friends and family using WhatsApp for free, even if they're in another country," the app description said.
Using your phone's Wi-Fi network rather than your cell plan's voice minutes, WhatsApp calling operates similarly to Skype, which requires an Internet connection to complete video and voice calls. The new feature will roll out slowly to iOS users over the next several weeks.
WhatsApp voice calling first launched in February as a limited, invitation-only feature for Android, and rolled out to all Android users at the end of March.
The new Calls tab shows a list of incoming, outgoing, and missed calls; users can make or receive phone calls from their Contacts list or while chatting.
Apple iPhone owners can look for the update in the iTunes App Store, and keep an eye out for the new Calls feature.
Other WhatsApp Version 2.12.1 updates include the ability to share photos, videos, and links from other applications directly to WhatsApp, as well as edit contacts without leaving the service.
Users can also tap the chat screen's quick camera button to capture photos or video, or quickly choose from the phone's camera roll. You can also send multiple videos at once, and crop and rotate clips before messaging them.
In January, WhatsApp introduced a Web client for in-browser chatting, though it only works with the Android, BlackBerry, BlackBerry 10, and Windows Phone versions of the app.