---
title: "How are blockchain mainnet upgrades done?"
url: "https://worldwiki.io/q/how-are-blockchain-mainnet-upgrades-done"
type: "question"
language: "en"
intent: "informational"
entity: "Blockchain Mainnet"
topic: "Blockchain"
published: "2026-09-18 07:10:23"
updated: "2026-09-18 16:10:23"
---

# How are blockchain mainnet upgrades done?

## 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.

## Answer

Other examples: Ethereum's Merge was executed on mainnet on 15 September 2022 after testnet rehearsals [11], and Bitcoin's Taproot soft fork activated at block 709,632 in November 2021 [12]. The Pectra announcement warned that non-upgraded nodes would only stay connected with peers that share their upgrade status [4].

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## Sources

1. [Blockchain Technology Overview (NISTIR 8202)](https://arxiv.org/abs/1906.11078) — National Institute of Standards and Technology (via arXiv) · evidence page: https://worldwiki.io/source/171
2. [Networks](https://ethereum.org/developers/docs/networks/) — ethereum.org · evidence page: https://worldwiki.io/source/172
3. [Holesky and Hoodi Testnet Updates](https://blog.ethereum.org/2025/03/18/hoodi-holesky) — Ethereum Foundation Blog · evidence page: https://worldwiki.io/source/173
4. [Pectra Mainnet Announcement](https://blog.ethereum.org/2025/04/23/pectra-mainnet) — Ethereum Foundation Blog · evidence page: https://worldwiki.io/source/174
5. [Holešky Testnet Shutdown Announcement](https://blog.ethereum.org/2025/09/01/holesky-shutdown-announcement) — Ethereum Foundation Blog · evidence page: https://worldwiki.io/source/175
6. [Solana Clusters](https://solana.com/docs/references/clusters) — Solana Foundation · evidence page: https://worldwiki.io/source/176
7. [Using a test network](https://bitcoincore.academy/testnets.html) — Bitcoin Core Onboarding · evidence page: https://worldwiki.io/source/177
8. [Genesis block](https://en.bitcoin.it/wiki/Genesis_block) — Bitcoin Wiki · evidence page: https://worldwiki.io/source/178
9. [Ethereum Launches Long-Awaited Decentralized App Network](https://www.coindesk.com/markets/2015/07/30/ethereum-launches-long-awaited-decentralized-app-network) — CoinDesk · evidence page: https://worldwiki.io/source/179
10. [EIP-155: Simple replay attack protection](https://eips.ethereum.org/EIPS/eip-155) — Ethereum Improvement Proposals · evidence page: https://worldwiki.io/source/180
11. [The Merge](https://ethereum.org/roadmap/merge/) — ethereum.org · evidence page: https://worldwiki.io/source/160
12. [Taproot](https://bitcoinops.org/en/topics/taproot/) — Bitcoin Optech · evidence page: https://worldwiki.io/source/181