Bitcoin's Evolving Ruleset: A Shift from Hardware-Based Security

The Bitcoin network has undergone significant changes since its major upgrade in 2017. While some upgrades altered transaction and scripting rules, the mining algorithm remained largely intact.

BTC retained SHA256d for block header hashing during proof-of-work mining, but this did not mean the protocol was frozen. Segregated Witness (SegWit) activated in August 2017, changing how transaction witness data was handled under consensus rules.

Taproot expanded scripting and signature capabilities while remaining backward compatible through a soft fork. Bitcoin Core 0.21.1 included Taproot activation logic before the upgrade became active in 2021.