Soft Fork

In relation to blockchain technology, a soft fork involves introducing changes to a blockchain’s underlining protocol or software that are minor in nature.

A fork, in programming terms, is just a modification to the code.

These software updates can take the form of new blockchain functionality, upgrades to network performance, enhancements that correct security issues, or even changes to the consensus rules that govern how blocks are created and validated on a blockchain.

Forks are necessary for providing decentralized blockchains a way to make changes to the blockchain since there isn’t a central authority governing all aspects of blockchain development and evolution.

Software changes can be minor in scope or they can dramatically alter the original ruleset that governs how a blockchain operates.

A soft fork is a minor change to the blockchain software that can easily be implemented into the existing blockchain without affecting or changing any of the old rules that existed before the fork.

This makes a soft fork backward-compatible, meaning that node operators who don’t upgrade their software can still interact on the same blockchain with node operators who do upgrade.

Network participants – developers, miners, and other node operators – who don’t upgrade will still find new blocks created after the fork as valid.

Since soft forks deal with minor changes only, soft forks don’t require all miners and node operators on the network to agree to run the new fork.

Only a majority is needed, making it faster to implement soft fork upgrades without causing significant issues with the entire node community.

After a hard fork occurs, two distinctly separate blockchains operating on their own now exist. Nodes that performed the hard fork are on one blockchain with the new rules, and the nodes that didn’t perform the hard fork remain on the original blockchain with the original rules.

There is no communication between the hard fork nodes and the non-hard fork nodes after.

The two networks will run in parallel, but any new blocks are that created will only exist on their respective blockchain.

An example of a real-world soft fork on the Bitcoin network is the Segregated Witness (SegWit) fork.

Related Terms

Fork

When developers make changes to a blockchain, such as adding new blockchain functionality, correcting security issues, creating entirely new coins, or even changing the consensus protocol that governs how blocks are created and validated on a blockchain.

Full Node

A type of node that participates in a blockchain network, performing some function for the network, like securing the network or validating transaction data. A full node stores a complete copy of the blockchain data. Information about every block and the recorded transactions within each block is available in the full copy of the blockchain.

Hard Fork

A Hard Fork is a permanent split of a blockchain into two separate networks that will coexist simultaneously, running in parallel, but not affecting one another.

Node

Any device that participates in a blockchain network. Normally, nodes are computers or servers that provide some function to the network they’re connected to. A node’s role is dictated by the protocol of the network.

Distributed Ledger Technology

A database that is used to record transactions across a network of devices, usually computers or servers. “Distributed” refers to how the nodes (or computers or servers) of the network are designed architecturally, and where they are located geographically. “Ledger” in this context, and traditionally, simply refers to a centralized database that is used to store financial records, such as a company’s financials, liabilities, revenues, owner’s equity, and other financial information. Now, combine the two ideas and you have a ledger that is distributed across many devices, instead of one device, in many different locations, possibly around the world. Even if one of those locations disappears, or a computer or server goes down, the ledger is still intact, still secure, and the data stored within the ledger can still be processed, validated, and authenticated to.