For some reason the app doesn't tell me if a certain person is online (only happens to a few contacts). These people aren't abroad or anything and they live quite close to me so I don't know what happened there but it is not the connection. I also find that messages on some chats are not being marked as read so along with the not showing if the person is online or not, I have no way of knowing if that person got the text. It also ends calls randomly.