Definition
A soft fork is a backward-compatible change to a blockchain’s consensus rules that tightens or restricts what is considered a valid block or transaction. Nodes that adopt the new rules enforce stricter validation, while nodes that do not upgrade can still recognize blocks as valid, provided block producers and validators follow the updated, more restrictive consensus conditions.
In Simple Terms
A soft fork is an update to a blockchain’s rules that makes them stricter without breaking compatibility with older software. Upgraded nodes apply the new, tighter rules, but older nodes can still see the new blocks as valid as long as everyone producing blocks follows the updated rule set.
Context and Usage
The term soft fork is used in discussions about blockchain governance, protocol upgrades, and changes to consensus rules. It is often contrasted with hard forks when describing how networks introduce new validation conditions for blocks and transactions. Soft forks are typically referenced when assessing how validators, node operators, and other participants coordinate around rule changes while maintaining a single recognized chain.