{"id":734,"slug":"how-are-blockchain-mainnet-upgrades-done","question":"How are blockchain mainnet upgrades done?","intent":"informational","language":"en","url":"https://worldwiki.io/q/how-are-blockchain-mainnet-upgrades-done","entity":{"slug":"blockchain-mainnet","name":"Blockchain Mainnet","url":"https://worldwiki.io/entity/blockchain-mainnet"},"answer":{"short_answer":"Mainnet upgrades are coordinated. Developers specify the change, activate it on one or more testnets, and then schedule mainnet activation at a set block height or epoch. Node operators have to install compatible client software before that point. Ethereum's Pectra upgrade, for example, ran on the Sepolia, Holešky and Hoodi testnets before mainnet activation on 7 May 2025. Nodes that do not upgrade can end up on an incompatible fork.","detailed_answer":"<p>Other examples: Ethereum's Merge was executed on mainnet on 15 September 2022 after testnet rehearsals <span class=\"ref\">[11]</span>, and Bitcoin's Taproot soft fork activated at block 709,632 in November 2021 <span class=\"ref\">[12]</span>. The Pectra announcement warned that non-upgraded nodes would only stay connected with peers that share their upgrade status <span class=\"ref\">[4]</span>.</p>","format":"paragraph","confidence":75,"verified_at":"2026-09-18 07:10:23","updated_at":"2026-09-18 16:10:23"},"sources":[{"id":171,"title":"Blockchain Technology Overview (NISTIR 8202)","url":"https://arxiv.org/abs/1906.11078","publisher":"National Institute of Standards and Technology (via arXiv)","type":"academic","accessed_at":"2026-09-18 18:01:27"},{"id":172,"title":"Networks","url":"https://ethereum.org/developers/docs/networks/","publisher":"ethereum.org","type":"official","accessed_at":"2026-09-18 18:01:28"},{"id":173,"title":"Holesky and Hoodi Testnet Updates","url":"https://blog.ethereum.org/2025/03/18/hoodi-holesky","publisher":"Ethereum Foundation Blog","type":"official","accessed_at":"2026-09-18 18:01:28"},{"id":174,"title":"Pectra Mainnet Announcement","url":"https://blog.ethereum.org/2025/04/23/pectra-mainnet","publisher":"Ethereum Foundation Blog","type":"official","accessed_at":"2026-09-18 18:01:29"},{"id":175,"title":"Holešky Testnet Shutdown Announcement","url":"https://blog.ethereum.org/2025/09/01/holesky-shutdown-announcement","publisher":"Ethereum Foundation Blog","type":"official","accessed_at":"2026-09-18 18:01:29"},{"id":176,"title":"Solana Clusters","url":"https://solana.com/docs/references/clusters","publisher":"Solana Foundation","type":"official","accessed_at":"2026-09-18 18:01:30"},{"id":177,"title":"Using a test network","url":"https://bitcoincore.academy/testnets.html","publisher":"Bitcoin Core Onboarding","type":"official","accessed_at":"2026-09-18 18:01:30"},{"id":178,"title":"Genesis block","url":"https://en.bitcoin.it/wiki/Genesis_block","publisher":"Bitcoin Wiki","type":"official","accessed_at":"2026-09-18 18:01:31"},{"id":179,"title":"Ethereum Launches Long-Awaited Decentralized App Network","url":"https://www.coindesk.com/markets/2015/07/30/ethereum-launches-long-awaited-decentralized-app-network","publisher":"CoinDesk","type":"news","accessed_at":"2026-09-18 18:01:33"},{"id":180,"title":"EIP-155: Simple replay attack protection","url":"https://eips.ethereum.org/EIPS/eip-155","publisher":"Ethereum Improvement Proposals","type":"official","accessed_at":"2026-09-18 18:01:33"},{"id":160,"title":"The Merge","url":"https://ethereum.org/roadmap/merge/","publisher":"ethereum.org","type":"official","accessed_at":"2026-09-18 18:01:18"},{"id":181,"title":"Taproot","url":"https://bitcoinops.org/en/topics/taproot/","publisher":"Bitcoin Optech","type":"official","accessed_at":"2026-09-18 18:01:33"}],"published_at":"2026-09-18 07:10:23"}