Will Miners Signal? Bitcoin's Next Segwit2x Lock-in Period Starts Today

A bitcoin scaling proposal is close to enact the Segregated Witness upgrade as step one of its larger roadmap.

AccessTimeIconJul 18, 2017 at 8:35 p.m. UTC
Updated Sep 11, 2021 at 1:32 p.m. UTC

Should certain timelines be met, bitcoin could soon be upgraded to support Segregated Witness (SegWit).

A long-proposed upgrade that would increase the transaction capacity of the bitcoin network, SegWit would be triggered if miners decide to support the BIP 91 code proposal, itself a part of the larger Segwit2x scaling initiative.

Currently, BIP 91 is close to the necessary threshold (80% of mining power), with mining pools representing about 76% of bitcoin's computing power seemingly making good on a promise to support the proposal.

That percentage of mining pools, though, must signal in a type of unison, during a signaling period.

Due to how the BIP 91 code is written, the 80% threshold must be reached within a 336-block period. But it's not just any consecutive 336-block period.

Instead, there are set windows where miners can signal support, meaning 269 of the consecutive 336 blocks within the period must signal with "bit 4" in the block header.

The next signaling period starts tonight at block 476,448, and will end at block 476,784, about two-and-a-half days from now.

If 80% of mining pools don't activate SegWit in the period that starts tonight, they'll have other opportunities before August 1 when another scaling proposal BIP 148 will activate. Although, this could lead bitcoin down a few different paths, as CoinDesk's visual guide to the scaling debate demonstrates.

For more news and updates, follow our "Bitcoin Scaling Watch" live blog, or track miners signaling for BIP 91 here.

Disclosure: CoinDesk is a subsidiary of Digital Currency Group, which helped organize the Segwit2x agreement.

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