Hard fork: The upgraded blockchain is now responsible for validating transactions, but the old blockchain no longer recognizes or records these blocks. This means that all users must update their programs to access the new blockchain.
Bifurcations are usually resolved with hardly any disruption. However, all differences of opinion about how bitcoin works within the community have proven irreconcilable in the past. The best example of this is bitcoin cash, which came about when bitcoin experienced a hard fork that also divided miners. From there, two different cryptocurrencies finally emerged, bitcoin and bitcoin cash, both with the same transactional past until July 2017.