SegWit Activation Locks In Through BIP 91
SegWit activation officially locks in as miner signaling reaches 80% under BIP 91, virtually guaranteeing August 1 activation.
On July 20, 2017, Segregated Witness officially locked in for activation after achieving sustained 80% miner signaling through the BIP 91 mechanism. The lock-in occurred at 00:06 GMT and represented the culmination of months of political struggle, technical preparation, and community organizing around Bitcoin's scaling solution.
With SegWit locked in through BIP 91, it was now virtually certain that SegWit would activate through the original BIP 141 mechanism before the August 1 UASF deadline, eliminating the risk of a contentious chain split and resolving Bitcoin's year-long scaling crisis. The achievement united nearly the entire mining community, with even staunch SegWit opponents like Jihan Wu's Antpool and ViaBTC ultimately signaling support.
The SegWit lock-in was one of the most significant moments in Bitcoin's history, resolving what had been its most serious governance crisis. The activation would bring important technical improvements including transaction malleability fixes, capacity increases through more efficient use of block space, and enablement of second-layer solutions like Lightning Network.
The lock-in demonstrated that Bitcoin's decentralized governance model could work, albeit through a messy process involving multiple competing proposals, grassroots organizing, corporate agreements, and strategic game theory. The only major mining pool that opposed SegWit to the very end was Roger Ver's bitcoin.com pool, highlighting the deep ideological divides that remained even as the immediate crisis was resolved.Markets responded enthusiastically to the lock-in, with Bitcoin's price rallying on the news and volatility declining as the primary uncertainty that had hung over Bitcoin for months was finally eliminated.