What upgrade activated in 2017 introduced SegWit?
Answer
Segregated Witness
What upgrade activated in 2017 introduced SegWit? Segregated Witness introduced the transaction-format upgrade known as SegWit.
SegWit was implemented through Bitcoin Improvement Proposal 141 and activated on 24 August 2017 at block 481,824. Its central design change separated signature data, called the witness, from the transaction’s main data structure. This allowed Bitcoin to handle more transaction data within its existing block framework.
The upgrade also fixed a problem called transaction malleability, in which an unconfirmed transaction’s identifier could be altered without invalidating the transaction itself. That fix helped make payment-channel systems such as the Lightning Network practical.
A common mix-up is confusing SegWit with Taproot. Taproot was a later Bitcoin upgrade, activated in 2021. Schnorr signatures are associated with Taproot, while SegWit is the 2017 soft fork that separated witness data and addressed malleability.