To counter this, on August 1, 2017, bitcoin went through a hard fork (when a single cryptocurrency is split in two due to changes in existing code, ...
source https://www.google.com/url?rct=j&sa=t&url=https://bitcoinexchangeguide.com/bitcoin-stash/&ct=ga&cd=CAIyGmM2Nzk3ODA2ZWViNjVjODI6Y29tOmVuOlVT&usg=AFQjCNGOJp8IlHgGnwvUcr4hco5CyzAcFQ
