Viber for Lumia 900, Lumia 800, Lumia 710 and Lumia 610, is updated to version 188.8.131.52, no official changelog, so we assume that it is a minor update to fix some bugs found in previous versions.
Viber for Windows Phone 7 lets you make free calls and send free text and photo messages to other Viber users, on any device, network and country!With Viber, your contacts on your device are also your Viber contacts, because Viber automatically detects your contacts who already have Viber. All you need to do is click on a name and start talking. No invites. No hassle. Viber’s user-friendly interface lets you easily perform calls and send messages. You will also be able to change your profile pic, see which of your phone contacts already has Viber and who else has just joined.
Viber for Lumia is available free on Windows Phone Store.
Download | WindowsPhone Store (only works from Nokia Lumia devices)