There is one rather significant limitation in the algorithm of crypto currency bitcoin: the total number of coins generated can not exceed more than 21 million. And at the moment they have generated more than 15 million. According to forecasts, taking into account, among other things, the complication of the crypto currency generation processes, this number of coins will be reached approximately in 2140. What will happen next with bitcoin is not entirely clear. Although at the end of October a new version of Bitcoin Gold crypto currency was created: although the role of this virtual currency is not entirely obvious, but apparently it is intended to replace the usual bitcoin in the rather distant future.