DOWN TO TWO STARS NOW. ERRATIC BEHAVIOR has increased, particularly when sending files. Mobile app continues to take a while to open, and lags when checking on specific messages or opening a new message to an individual. When sending or forwarding messages or files, on screen it shows two check marks, indicating (I assume, all sent) only to double check and find that it still is trying to send the messages or files. Internet connection now good, so it's down to the Viber app Tech Support?