Bitcoin Soft Forks — Consensus Activation Registry (P2SH to Taproot)

Every consensus-changing Bitcoin soft fork, from P2SH to Taproot — BIP numbers, activation mechanism, block height and date, and what each one changed. Free CSV/JSON + REST under CC BY 4.0.

Quick answer

A Bitcoin soft fork is a backward-compatible tightening of the consensus rules: nodes that don't upgrade still accept the new blocks, so the network never splits if a majority of hashpower enforces it. Nearly every capability Bitcoin has gained — P2SH multisig, time-locks, SegWit, Taproot — arrived as a soft fork. This registry lists 8 consensus-changing soft forks with their BIP numbers, activation mechanism, activation block height and date, and what each one changed.

From P2SH (2012) to Taproot (2021), each soft fork tightened the rules without splitting the chain. The activation method evolved from timestamp flag days to IsSuperMajority to BIP9 version bits to Speedy Trial — increasingly miner-signalled, with users (UASF) as the ultimate backstop.

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Soft fork	BIP(s)	Activation mechanism	Block	Activated	Status	What it changed
BIP30 — Duplicate-TXID rule	30	Flag day (block timestamp)	91,842	2012-03-15	Active	Disallowed a block containing a transaction whose ID duplicates an existing unspent transaction, closing a coinbase-overwrite flaw.
P2SH — Pay-to-Script-Hash	16	Flag day (block timestamp)	173,805	2012-04-01	Active	Introduced Pay-to-Script-Hash (the '3' addresses): senders pay to a hash of a redeem script that the recipient supplies when spending — the basis for practical multisig.
BIP34 — Height in coinbase	34	IsSuperMajority (75% then 95%)	227,931	2013-03-24	Active	Required the block height in the coinbase and bumped block version to 2, preventing duplicate coinbase txids and introducing version-based soft-fork signalling.
BIP66 — Strict DER signatures	66	IsSuperMajority (95%)	363,725	2015-07-04	Active	Enforced strict DER encoding of ECDSA signatures, removing an OpenSSL-dependent malleability source. Its activation caused a brief accidental chain split among non-upgraded miners.
CLTV — CheckLockTimeVerify	65	IsSuperMajority (95%)	388,381	2015-12-14	Active	Added OP_CHECKLOCKTIMEVERIFY, enabling outputs spendable only after an absolute block height or time — a building block for payment channels and escrow.
CSV — Relative lock-time	68, 112, 113	BIP9 version bits (95%)	419,328	2016-07-04	Active	Relative lock-time (BIP68), OP_CHECKSEQUENCEVERIFY (BIP112) and median-time-past (BIP113) — together enabling bidirectional payment channels and the Lightning Network.
SegWit — Segregated Witness	141, 143, 147	BIP9 version bits + BIP91 lock-in	481,824	2017-08-24	Active	Moved signature (witness) data outside the txid, fixing transaction malleability, raising effective capacity via block weight, and laying the groundwork for Lightning and Taproot.
Taproot — Schnorr + Tapscript	340, 341, 342	Speedy Trial (BIP9, 90%)	709,632	2021-11-14	Active	Schnorr signatures (BIP340), Taproot (BIP341) and Tapscript (BIP342) — key aggregation and Merkelized script paths giving multisig and complex scripts better privacy and efficiency.

Source: the Bitcoin BIP repository and the canonical activation heights in Bitcoin Core. Related glossary: soft fork, P2SH, SegWit, Taproot, version bits, CLTV, CSV. See the open data hub.

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Last reviewed June 19, 2026.