Speedy Trial

Speedy Trial is a soft-fork activation strategy, proposed by David Harding and based on an idea from Russell O'Connor, designed to let a mature, uncontroversial protocol change either activate or fail fast — in about three months — rather than leaving the network in suspense for a year or more. It is best known as the method that activated Taproot in 2021, and it emerged as a pragmatic compromise from one of the more contentious process debates in Bitcoin's recent history.

How it works

Speedy Trial compresses the miner-signaling phase of a soft-fork activation into a short, fixed window of roughly three months. During that window, miners signal readiness using version bits in the blocks they mine. If at least 90% of blocks within a single 2,016-block retarget period signal support, the change locks in — and then activates at a predetermined block height set comfortably in the future, giving node operators, wallets, and miners time to upgrade before the rules take effect. If the window closes without any period reaching the threshold, the attempt simply expires with no activation and no lasting state; developers can regroup and re-propose with a different mechanism. The design deliberately separates the decision (quick) from the deployment (unhurried).

Why the design looks this way

The mechanism is a study in reading failure modes. The older BIP 9 approach let a small minority of non-signalling hashrate stall a widely supported change indefinitely — the frustration that fueled the 2017 UASF movement and BIP 148. The stricter BIP 8 path, with mandatory lock-in on timeout, guarantees activation but forces a confrontation if miners abstain. Speedy Trial threads the needle: it costs little time if miners fail to signal (fail fast, try another way), while its 90% threshold and short window remove the incentive to posture. In the terminology of the underlying parameters, it used BIP 8-style mechanics with lock-in-on-timeout set to false — a trial, not an ultimatum. Critics noted the flip side: by returning to miner signaling at all, it deferred the harder philosophical question of who ultimately decides upgrades, a question the UASF approach answers very differently.

Its place in history

Speedy Trial's one deployment was a clean success. Taproot signaling began in May 2021, reached the 90% threshold and locked in during June 2021, and activated at block 709,632 in November 2021 — delivering Schnorr signatures and Taproot outputs without a chain split or standoff. That record makes it a leading candidate template for future upgrades, though the Bitcoin development community treats each activation as its own decision rather than settled precedent; the "how do we activate" debate resumes every time a new fork candidate matures. It remains one technique within the broader BIP process conversation about how a leaderless network changes its own rules — which is, at bottom, a decentralization question: any activation method encodes a claim about whose consent counts.

One design element deserves its own mention: the fixed activation height. Even after miners locked Taproot in during June, the rules did not take effect until November — a deliberate five-month runway for node operators to upgrade, since a soft fork is only safe when an economic majority of nodes enforces the new rules at the moment they activate. Miner signaling, in this reading, was never a vote on the change's merits; it was a coordination beacon indicating that hashrate was ready and that blocks violating the new rules would be orphaned. Separating readiness signaling from rule enforcement is the quiet insight that let Speedy Trial satisfy both the miner-signaling pragmatists and the user-sovereignty camp.

See soft fork for what is being activated, and Taproot for the upgrade Speedy Trial carried over the line.