The WhatsApp app for Windows Phone today received a major update: Now you can make free voice calls with it.

That feature arrived on Android in March and on iOS in April.

The new version of the app also lets you send audio files — if you’re running Windows Phone 8.1 or a later release.

Facebook bought WhatsApp for $22 billion last year, and now the app has more than 800 million monthly active users.

Facebook doesn’t plan to charge for VoIP calls, chief executive Mark Zuckerberg said in April.