The History of Bitcoin's Major Forks
A factual overview of the significant protocol upgrades and contentious splits in Bitcoin's history.
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What to remember
- SegWit and Taproot were significant, backward-compatible soft-fork upgrades.
- Bitcoin Cash resulted from a 2017 contentious hard fork over block-size scaling.
- A forked asset becomes fully independent from the original chain going forward.
- Bitcoin's protocol history shows both smooth upgrades and contentious splits.
Soft forks: backward-compatible upgrades
Several significant Bitcoin upgrades have shipped as soft forks — backward-compatible rule changes that don't require every node to upgrade simultaneously, including Segregated Witness (SegWit) in 2017 and Taproot in 2021, both expanding the network's technical capabilities without splitting it.
Bitcoin Cash: a contentious hard fork
In 2017, a disagreement over how to scale Bitcoin's transaction capacity led to a contentious hard fork, creating Bitcoin Cash as a separate network and asset with a larger block size, splitting from Bitcoin's original chain and community.
Why SegWit and Taproot stayed backward-compatible while the Bitcoin Cash split did not -- the same mechanism, generalized.
Why this history matters
- It illustrates that Bitcoin's protocol can and does change, through both smooth, backward-compatible processes and contentious splits.
- It shows that a fork can create an entirely new, independent asset when a network's participants can't reach consensus on a proposed change.
A forked asset is not the "same" Bitcoin
Bitcoin Cash and other assets forked from Bitcoin's history are separate, independent networks and assets going forward — sharing a common history doesn't make them interchangeable or equivalent after the split.
What to remember
- SegWit and Taproot were significant, backward-compatible soft-fork upgrades.
- Bitcoin Cash resulted from a 2017 contentious hard fork over block-size scaling.
- A forked asset becomes fully independent from the original chain going forward.
- Bitcoin's protocol history shows both smooth upgrades and contentious splits.