Facebook's buy of WhatsApp places the world's largest social network closer to the heart of mobile communications. Reuters

WhatsApp voice calling is finally available for Windows Phone users. It is on the latest version of WhatsApp, which can be downloaded from the Windows Phone Store. The new app also comes with the ability to send audio files to Windows Phone 8.1 users

The latest version of WhatsApp for Windows Phone weighs 19MB. Users can either install the new version or uninstall the existing app and download the latest version. After installing the new app, users will see a new "Chats" tab along with other tabs for Chats, Favorites and All.

The voice-calling feature uses the data connection of the handset to make free calls. The newly released app comes with a ‘delete call history’ option. As revealed by WM Power User through latest beta version of WhatsApp, the new app allows users to delete incoming or outgoing calls from the call history.

In the previous version of WhatsApp, users were unable to send audio files to other users. However, while chatting to someone in the new app, users can select the Audio option under the Attach Media icon. Through the Audio option, users can select and send audio files from various locations, such as Recent, This Device, Removable Disk, Dropbox and OneDrive.

Android and iOS users have been using the WhatsApp voice-calling feature for a couple of months. However, it is only now that the feature has finally arrived for Windows Phone users. Rival apps like Skype, LINE, Tango, and Viber support the video-calling feature. Press and Update’s report from April claims that the free video calling service will soon arrive for WhatsApp on Windows Phone. Wine Beta claims that in the near future WhatsApp will get integrated with Skype through a new Call via Skype feature. It will let users to initiate a Skype video call while having a text conversation.

As WhatsApp on Android allows users to save chat conversation on Google Drive, even Windows Phone users are rumored to receive support for saving a chat conversation on OneDrive cloud storage. As of this writing, there is no confirmation from WhatsApp on the arrival of video calling and OneDrive support for Windows Phone users.

WhatsApp was acquired by Facebook last year in February. Currently, it has over 800 million active users per month. Apart from Android, iOS and Windows Phone, the popular instant messaging app is also available for multiple mobile OS platforms like BlackBerry, BlackBerry 10 OS, Symbian Tizen, Nokia Series 40.