Overview
A soft fork is a backward-compatible protocol upgrade where old nodes still accept new blocks. It tightens rules without splitting the chain. It is a less disruptive upgrade path.
How It Works
New rules are stricter than old ones, so upgraded nodes produce blocks old nodes still accept. Old nodes may accept invalid-by-new-rules blocks, but the majority rule prevails. Activation usually requires majority hash power or stake.
Why It Matters
Soft forks enable upgrades with less disruption and community risk than hard forks. They are common for tightening consensus rules. Their backward compatibility eases adoption.
Related Concepts
Soft Forks contrast with Hard Forks and relate to Consensus upgrades. They are a less disruptive Protocol change path.