In this episode of Bitcoin, Explained, hosts
Aaron van Wirdum and Sjors Provoost discuss URSFs, which stands for
either User Rejected Soft Forks or User Resisted Soft Forks,
depending on who you ask. URSFs are a recently introduced tool in
Bitcoin’s upgrade mechanism toolkit.
In the first part of the episode, Aaron and Sjors explain that
URSFs are best considered the mirror equivalent of UASFs (User
Activated Soft Forks) with mandated signaling. Where UASFs will
towards the end of a soft fork activation window reject blocks that
don’t signal readiness for a soft fork, URSFs will reject blocks
that do signal. If both UASF and URSF clients
are deployed, they would in principle create a split in the
blockchain.
In the second part of the episode, the duo outlines the various
soft fork upgrade mechanisms, ranging from MASFs (Miner Activated
Soft Forks), flag day activated UASFs and mandated signaling UASFs.
Aaron then explains why he believes mandated signaling UASFs are
his preferred method of deploying soft forks, and why he thinks
URSFs should in the future be offered as an added option for users
who prefer to reject the soft fork.
Finally, Sjors lays out the “rough consensus” guidelines as used in
context of the Internet Engineering Taskforce (IETF), and how this
applies to Bitcoin upgrades.
About the Podcast
Bitcoin Magazine's Technical editor Aaron van Wirdum teams up with Bitcoin core contributor Sjors Provoost to explain Bitcoin one episode at a time.