Bitcoin glossary
The 2017 upgrade that fixed malleability and made transactions smaller.
Segregated Witness (SegWit), activated in 2017, restructured how signatures are stored in transactions — fixing transaction malleability (a prerequisite for Lightning) and effectively increasing block capacity. SegWit addresses start with bc1q and produce cheaper transactions.
Its activation ended the “blocksize war”, Bitcoin’s formative governance conflict, demonstrating that users running nodes — not miners or companies — hold the final say over the rules.