WeChat, China’s hot chat app — with around 600 million users — today rolled out group video calling for up to nine people, on iOS. The update comes just weeks after WeChat introduced video calling on Windows.

One of its smaller competitors in Asia, Japan-based Line, recently revamped its Android app with a new focus on low-cost calling. In general, video-calling apps, like Skype, are looking for new ways to keep users from moving to competing services. (Skype just rolled out shareable chat links to take on Google Hangouts.)

Screen Shot 2015-10-20 at 17.06.31It’s tough to maintain a lead in the space, because consumers are spoiled for choice. But locking users into video calling in an app means they are more likely to end up using the other features and services offered as well — something WeChat already excels at.

This update also brings a new feature to the WeChat in-app fitness tracker, allowing users to “create your own fitness friends list and see how you match up by following their fitness trends.” (We took a deeper look at that here.)