Yestarday i visit a website called https://www.bitminer.world. its a cloud mining website in which they said that they gave us free 40 satoshi/per minute and after your account balance reached to 0.005 bitcoin than you do with draw.
After few days when my balance reached to 0.008 btc and i do withdraw suddenly a meesage popups in which they say that "You need to Upgrade your BitMiner to make withdrawals. " Its a scam because they do a fake promise that they gave us free satoshi but unfortunately they are lying please dont visit this website