Fork

A fork is a divergence in blockchain history or rules. Temporary forks happen when two valid blocks are found near the same time; permanent forks happen when participants follow incompatible rules or intentionally split.

A hard fork changes consensus rules in a way older nodes do not accept. If not everyone upgrades to the same rules, the network can split into separate chains with separate assets and communities.

A soft fork tightens rules so upgraded nodes enforce new restrictions while older nodes may still see new blocks as valid. Soft forks still require careful activation because non-upgraded users may not fully validate new behavior.

Fork planning must consider replay protection, wallet support, exchange policies, miner or validator support, and communication. Poor coordination can confuse users and create loss risks.