Bitcoin Forks FAQ
A beginner-friendly guide to Bitcoin forks - what they are, what types exist, and what’s being discussed today.
Quick Definitions
- Fork - A change to Bitcoin’s rules. Can be routine (everyone agrees) or contentious (they don’t).
- Soft fork - Tightens rules. Backward-compatible. Non-upgraded nodes still follow the chain.
- Hard fork - Changes rules in ways old nodes reject. Can cause permanent chain splits.
- Temporary soft fork - A soft fork with a built-in expiry date.
- BIP - Bitcoin Improvement Proposal. The standard format for proposing changes. Anyone can write one. Full list
- UASF - User-Activated Soft Fork. Activated by node operators on a flag day, not by miner signaling.
- MASF - Miner-Activated Soft Fork. Activated when a threshold of blocks signal support (historically 90-95%).
- Activation threshold - The percentage of blocks that must signal support before new rules take effect.
- Nakamoto consensus - Bitcoin’s majority-rule mechanism (white paper, section 6). Proof-of-work and the longest-chain rule create economic incentives for convergence.
Historical Soft Forks
Every soft fork in Bitcoin’s history has resulted in network convergence - no chain splits.
| Year | Fork | Type | What it did |
|---|---|---|---|
| 2012 | P2SH (BIP-16) | MASF | Pay-to-script-hash for complex spending conditions |
| 2012 | BIP-34 | MASF | Block height in coinbase transactions |
| 2015 | CLTV (BIP-65) | MASF | Absolute time locks |
| 2015 | BIP-66 | MASF | Strict DER signature encoding |
| 2016 | CSV (BIP-68/112/113) | MASF | Relative time locks |
| 2017 | SegWit (BIP-141) | UASF/MASF | Witness separation, malleability fix, capacity increase |
| 2021 | Taproot (BIP-340/341/342) | MASF | Schnorr signatures, MAST, improved privacy |
Historical Hard Forks
Hard forks without overwhelming consensus create permanent chain splits.
| Year | Fork | What happened |
|---|---|---|
| 2017 | Bitcoin Cash (BCH) | Increased block size to 8 MB. Permanent split. |
| 2017 | Bitcoin Gold (BTG) | Changed PoW to Equihash. Permanent split. |
| 2018 | Bitcoin SV (BSV) | Split from BCH, block size to 128 MB. |
Current Proposals
| Proposal | Type | Status |
|---|---|---|
| BIP-110 | UASF (temporary soft fork) | Proposed - data-reduction rules, auto-expires ~1 year |
| BIP-54 | Soft fork | Draft - consensus cleanup (timewarp fix, validation limits, Merkle fix) |
| eCash | Hard fork | Proposed - see ecash.com |
General FAQ
Common questions about Bitcoin governance, terminology, and discussion norms - including why the word “consensus” should be avoided, who decides Bitcoin’s rules, relay policy vs consensus rules, and more.
Common Talking Points
Data-driven responses to claims that come up repeatedly: “there is no way of stopping spam”, “this is censorship”, “miners should decide”, “dynamic fees already solve this”, “it doesn’t actually stop spam”, and more.
Getting Involved
- Run a node - The most direct way to participate in Bitcoin governance
- Contribute data - Empirical analysis is more valuable than opinion
- Contribute to this FAQ - Submit PRs, open issues, suggest questions
Learn More
- Bitcoin white paper - The founding document
- BIP repository - All proposals
- bip110.org - BIP-110 community hub, installation guides, FAQ
- Bitcoin Block Space Weekly - Empirical block space analysis (Renaud Cuny)
Community effort. Does not represent any individual or organization. Corrections welcome via PR.