{"id":37537,"date":"2022-05-20T09:03:00","date_gmt":"2022-05-20T06:03:00","guid":{"rendered":"https:\/\/forklog.com\/en\/?p=37537"},"modified":"2025-08-29T18:12:48","modified_gmt":"2025-08-29T15:12:48","slug":"what-is-a-hard-fork","status":"publish","type":"post","link":"https:\/\/forklog.com\/en\/what-is-a-hard-fork\/","title":{"rendered":"What is a hard fork?"},"content":{"rendered":"<div class=\"wp-block-text-wrappers-cards single_card\">\n<h2 class=\"card_label\"><strong>Key points<\/strong><\/h2>\n<ul class=\"wp-block-list\">\n<li>A hard fork is a way to make significant changes to a blockchain protocol\u2019s code. The term comes from the English word \u201cfork\u201d.<\/li>\n<li>A hard fork is also a means for the community to reach consensus on proposed changes.<\/li>\n<li>Hard forks are sometimes used to launch new crypto projects.<\/li>\n<\/ul>\n<\/div>\n<div class=\"wp-block-text-wrappers-cards single_card\">\n<h2 class=\"card_label\">Why have a hard fork?<\/h2>\n<p>Every <a href=\"https:\/\/forklog.com\/en\/news\/what-is-blockchain-2\">blockchain<\/a> runs on a protocol\u2014an application composed of various components. The code of most popular blockchain projects is open source. This means it is published in full and can be freely copied.<\/p>\n<p>Blockchain protocol code is continually refined: bugs and vulnerabilities are removed and improvements added. Some changes can be substantial. In such cases developers create a hard fork: rather than altering the current protocol, they make a parallel copy and add new code to it. Validators or operators of Bitcoin nodes then migrate to the new version of the protocol\u2014if they agree with the changes.<\/p>\n<p>This approach preserves the blockchain\u2019s stability, since the current protocol remains unchanged and is not exposed to upgrade risks.<\/p>\n<p>Hard forks are used for major upgrades, but they can also resolve crises. For example, after The DAO was hacked in 2016, Ethereum developers used a hard fork to \u201creturn\u201d to owners funds worth about $55m that had been stolen\u2014a very significant sum for the crypto industry at the time.<\/p>\n<\/div>\n<div class=\"wp-block-text-wrappers-cards single_card\">\n<h2 class=\"card_label\">Who invented the hard fork?<\/h2>\n<p>Forks are widely used in software development. Most source-code libraries are managed with Git, the world\u2019s most popular version-control system. It allows developers to create copies of a current library (branches of the original). Thanks to this, they can test changes needed in the main library without risking \u201cbreaking\u201d it. The copy retains a link to the parent branch.<\/p>\n<p>As development progresses, new branches often grow from the original library, and these can in turn be copied. The application\u2019s change history thus takes a tree-like form, resembling the tines of a fork with a single handle (hence the name).<\/p>\n<p>Much the same happens with a blockchain protocol.<\/p>\n<\/div>\n<div class=\"wp-block-text-wrappers-cards single_card\">\n<h2 class=\"card_label\"><strong>Who takes part in a hard fork?<\/strong><\/h2>\n<p>Typically a hard fork follows lengthy discussion and consensus within a project\u2019s community. Developers first propose a change. It is debated, refined and tested, and finally released.<\/p>\n<p>If the upgrade is major and involves not only technical changes but also, say, tokenomics, debate can extend beyond developers. In Bitcoin there is a formal system for protocol-improvement proposals called Bitcoin Improvement Proposal (BIP). Developers of Ethereum <a href=\"https:\/\/eips.ethereum.org\/\" target=\"_blank\" rel=\"noreferrer noopener\">follow<\/a> a similar approach.<\/p>\n<p>To activate a hard fork, writing new code is not enough; approval from most other participants is required. Besides developers, the other key constituency is validators who run the network\u2019s nodes. The blockchain\u2019s stable, healthy operation\u2014and thus the whole project\u2014depends on them.<\/p>\n<p>Validators know what blockchain users need and can voice opinions on proposed changes. If they do not support an upgrade, they simply will not switch their nodes.<\/p>\n<p>Crucially, a genuine blockchain protocol cannot be updated unilaterally, without the community\u2019s consent, because decentralisation applies not only to the network but also to its software layer.<\/p>\n<p>The <a href=\"https:\/\/forklog.com\/en\/news\/what-is-terra-luna\">Terra<\/a> episode illustrated this. After the dramatic collapse of the UST stablecoin and the LUNA native cryptocurrency, the project\u2019s founder, Do Kwon, proposed issuing a new digital currency via a hard fork. In his view it could be used to compensate holders of the devalued coins. Many in the Terra community disagreed.<\/p>\n<\/div>\n<div class=\"wp-block-text-wrappers-cards single_card\">\n<h2 class=\"card_label\"><strong>How do new blockchain projects emerge from hard forks?<\/strong><\/h2>\n<p>If most nodes support a hard fork, the network migrates to the new version. In PoW blockchains such as Bitcoin, miners must also signal readiness to adopt the upgrade.<\/p>\n<p>But sometimes a hard fork splits the community: some nodes support the upgrade while others do not. The blockchain can then divide into two chains: one runs with the upgrade, the other continues the old branch, adding its own changes.<\/p>\n<figure class=\"wp-block-image size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/forklog.com\/wp-content\/uploads\/FORK-min-1024x819.png\" alt=\"What is a hard fork?\" class=\"wp-image-107299\" width=\"768\" height=\"614\" srcset=\"https:\/\/forklog.com\/wp-content\/uploads\/FORK-min-1024x819.png 1024w, https:\/\/forklog.com\/wp-content\/uploads\/FORK-min-300x240.png 300w, https:\/\/forklog.com\/wp-content\/uploads\/FORK-min-768x614.png 768w, https:\/\/forklog.com\/wp-content\/uploads\/FORK-min.png 1200w\" sizes=\"auto, (max-width: 768px) 100vw, 768px\" \/><\/figure>\n<p>This is what happened after The DAO hack: most supported Vitalik Buterin\u2019s proposal to compensate victims via a hard fork, but part of the community disagreed. The result was Ethereum Classic.<\/p>\n<p>A similar episode occurred with Bitcoin: differing views on scaling the first cryptocurrency via protocol changes led some developers and miners in 2017 to <a href=\"https:\/\/forklog.com\/en\/news\/what-is-bitcoin-cash-bch-and-how-did-it-emerge\">form<\/a> the Bitcoin Cash project.<\/p>\n<p>Projects whose code has been copied from another protocol are also called forks. That is how <a href=\"https:\/\/forklog.com\/en\/news\/in-uniswap-fork-800-million-of-assets-were-locked-three-days-after-launch\">SushiSwap appeared<\/a>, whose creators made only minor edits to the source code of the Uniswap decentralised exchange.<\/p>\n<\/div>\n<div class=\"wp-block-text-wrappers-cards single_card\">\n<h2 class=\"card_label\">How does a hard fork affect a cryptocurrency\u2019s price?<\/h2>\n<p>Events of this kind almost always affect prices. If a hard fork is meant to resolve major issues, enjoys consensus and is anticipated by the community, the network\u2019s native asset will probably rise.<\/p>\n<p>But if a hard fork splits the community, fails to advance the project or does not go to plan, the native cryptocurrency may well lose value. Most often that reflects investors\u2019 doubts about the blockchain\u2019s prospects.<\/p>\n<p>Either way, a hard fork introduces uncertainty.<\/p>\n<\/div>\n<div class=\"wp-block-text-wrappers-cards single_card\">\n<h2 class=\"card_label\"><strong>How does a soft fork differ from a hard fork?<\/strong><\/h2>\n<p>If a hard fork is a \u201chard\u201d upgrade that requires moving to a new branch, a <a href=\"https:\/\/forklog.com\/en\/news\/what-is-a-user-activated-soft-fork-uasf\">soft fork<\/a> is a \u201csoft\u201d, usually minor change that does not require restarting the network on a new protocol.<\/p>\n<\/div>\n<div class=\"wp-block-text-wrappers-cards single_card\">\n<h2 class=\"card_label\">Further reading<\/h2>\n<p>What are ERC-20 tokens?<\/p>\n<p><a href=\"https:\/\/forklog.com\/en\/news\/what-is-the-blockchain-trilemma\">What is the blockchain trilemma?<\/a><\/p>\n<p><a href=\"https:\/\/forklog.com\/en\/news\/what-is-bitcoin-cash-bch-and-how-did-it-emerge\">What is Bitcoin Cash (BCH) and how did it appear?<\/a><\/p>\n<p><a href=\"https:\/\/forklog.com\/en\/news\/what-is-uniswap-uni\">What is Uniswap?<\/a><\/p>\n<p><a href=\"https:\/\/forklog.com\/en\/news\/what-is-coin-burning-and-how-does-it-affect-prices\">What is coin burning and how does it affect the price?<\/a><\/p>\n<p>What is staking?<\/p>\n<p><a href=\"https:\/\/forklog.com\/en\/news\/recommender-systems-what-they-are-and-how-they-work\">What are recommender systems?<\/a><\/p>\n<p><a href=\"https:\/\/forklog.com\/en\/news\/what-is-solana-sol\">What is Solana?<\/a><\/p>\n<p>What are layer-two scaling solutions?<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Why are hard forks needed? Why do they require community consensus? What happens if consensus cannot be reached? Explained in new cards.<\/p>\n","protected":false},"author":1,"featured_media":37538,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"select":"1","news_style_id":"1","cryptorium_level":"2","_short_excerpt_text":"","creation_source":"","_metatest_mainpost_news_update":false,"footnotes":""},"categories":[2113],"tags":[2115,268,1134],"class_list":["post-37537","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-cryptorium","tag-101-technical-foundations","tag-hardfork","tag-technical-updates"],"aioseo_notices":[],"amp_enabled":true,"views":"109","promo_type":"1","layout_type":"1","short_excerpt":"","is_update":"","_links":{"self":[{"href":"https:\/\/forklog.com\/en\/wp-json\/wp\/v2\/posts\/37537","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/forklog.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/forklog.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/forklog.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/forklog.com\/en\/wp-json\/wp\/v2\/comments?post=37537"}],"version-history":[{"count":1,"href":"https:\/\/forklog.com\/en\/wp-json\/wp\/v2\/posts\/37537\/revisions"}],"predecessor-version":[{"id":37539,"href":"https:\/\/forklog.com\/en\/wp-json\/wp\/v2\/posts\/37537\/revisions\/37539"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/forklog.com\/en\/wp-json\/wp\/v2\/media\/37538"}],"wp:attachment":[{"href":"https:\/\/forklog.com\/en\/wp-json\/wp\/v2\/media?parent=37537"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/forklog.com\/en\/wp-json\/wp\/v2\/categories?post=37537"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/forklog.com\/en\/wp-json\/wp\/v2\/tags?post=37537"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}