I mailed Viber Team yesterday about problems we are getting using viber. They replied me back and they said the app available on the BBWorld is not a native Blackberry app. It is an Android based app so they can't promise it's full functionality. Further, they added that they have no future plans for developing native BB Viber App soon. I urge all my friends on this forum to mail to viber support tea, to build a native app for us or mail the blackberry support team to bring native viber app with full functionality.