Speedy Trial

Speedy Trial is a soft-fork activation strategy proposed by David Harding, based on an idea from Russell O'Connor, designed to let a mature, uncontroversial proposal either activate or fail fast rather than dragging on for a year. It was built on the BIP 8 mechanism with the lock-in-on-timeout parameter set to false, but with the signaling window compressed to roughly three months.

How it works

During the short window, miners signal readiness using version bits. If at least 90% of blocks in a retarget period signal, the change locks in and activates at a predetermined height; if the window closes without reaching that threshold, the attempt simply fails and can be re-proposed. Keeping the window brief avoids a long political standoff while still giving the network a clear go or no-go answer.

Its place in history

Speedy Trial was the method that successfully activated Taproot, locking in during 2021 and activating at block 709,632 in November of that year. It can be seen as a pragmatic middle path between the miner-driven BIP 9 approach and the user-enforced mandatory activation that BIP 8 allows, reducing the risk of a small minority of non-signalling hashrate vetoing a change.

Speedy Trial is one technique within the broader debate over soft-fork activation; it is closely tied to the version bits signaling format it inherits.