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Bitcoin Data GuideBitcoin Reference

Protocol & Mining

The protocol and upgrade tracker

Every change that has altered Bitcoin's consensus rules, with the BIP that defines it, the mechanism that activated it, and the date or block height at which it took effect. Deployed changes and open proposals are listed separately, so a proposal is never mistaken for a rule the network enforces.

Protocol referenceSource: Bitcoin BIPs and Bitcoin Core release notesDates and block heights are taken from the cited BIPs and release notes.

How to read the tracker

Bitcoin has no release process. There is no vendor that ships a new version to every participant and no moment at which the network switches over. A rule change takes effect only when enough of the network enforces it that blocks violating it are rejected, and that threshold is reached by voluntary adoption. The tracker records the changes that crossed that threshold, and keeps them apart from the proposals that have not.

Each row names the BIP that defines the change, the mechanism the network used to activate it, and the date or block height at which it took effect. The mechanism column is deliberately specific: a flag day, a version-number supermajority, version-bits signalling under BIP 9, and the Speedy Trial variant are different procedures with different failure modes, and the version bits and soft-fork signalling page explains how the signalling mechanisms work.

The specification column links to the primary document — the BIP itself, or the Bitcoin Core release notes that record which rules a release enforces. The final column links to the article on this site that explains the change in full, so a reader can move from the register to the explanation without leaving the reference.

Deployed changes

These changes are enforced by the network today. Each was deployed through a mechanism that let participants opt in, and each is defined by a proposal that can be read at the source.

Deployed Bitcoin consensus changes, with their BIP, activation mechanism, activation date and specification.
BIPChangeActivation mechanismActivation / statusSpecificationExplained by
BIP 16DeployedPay to Script Hash (P2SH)Miner poll, then flag day1 April 2012 · block 173,805BIP 16Address types
BIP 30DeployedNo duplicate transaction IDsFlag day15 March 2012BIP 30Transaction lifecycle
BIP 34DeployedBlock height in the coinbaseVersion-number supermajority25 March 2013 · block 227,931BIP 34How nodes verify
BIP 66DeployedStrict DER signature encodingVersion-number supermajority4 July 2015 · block 363,725BIP 66Major protocol upgrades
BIP 65DeployedOP_CHECKLOCKTIMEVERIFYVersion-number supermajority14 December 2015 · block 388,381BIP 65Bitcoin Script
BIP 68, 112, 113DeployedRelative timelocks (CSV)BIP 9 version bits, bit 04 July 2016 · block 419,328BIP 68Bitcoin Script
BIP 141, 143, 147DeployedSegregated Witness (SegWit)BIP 9 version bits, bit 1, with BIP 91 and BIP 14824 August 2017 · block 481,824BIP 141SegWit explained
BIP 340, 341, 342DeployedTaproot and Schnorr signaturesSpeedy Trial (BIP 8, bit 2)14 November 2021 · block 709,632BIP 341Taproot explained

Proposed and in progress

A published proposal is not a change to the network. None of the changes below is a deployed feature of Bitcoin; each is a proposal under discussion, and the status column says so. The process a proposal must pass before it could be adopted is described on the how BIPs work page.

Proposed Bitcoin consensus changes that have not been deployed, with their BIP, proposed mechanism and current status.
BIPChangeActivation mechanismActivation / statusSpecificationExplained by
BIP 118ProposedSIGHASH_ANYPREVOUTSoft fork, activation mechanism undecidedProposed — not deployedBIP 118SIGHASH_ANYPREVOUT
BIP 119ProposedOP_CHECKTEMPLATEVERIFY (covenants)Soft fork, activation mechanism undecidedProposed — not deployedBIP 119Covenants
BIP 300, 301ProposedDrivechainsSoft fork secured by miner signallingProposed — not deployedBIP 300Drivechains
BIP 345ProposedOP_VAULTSoft fork, activation mechanism undecidedProposed — not deployedBIP 345Covenants

Sources

  • Bitcoin BIPs, the proposal repository — the specification behind every row in the tracker.
  • Bitcoin Core, implemented BIPs — the record of which consensus rules each release enforces.
  • Bitcoin Core, release notes — the deployment history behind each activation date.

Related reading