Entries → protocol timelines
Network Upgrade History: A Reference Timeline
Major protocol changes across the largest networks, with dates and what each one actually changed.
| Entry type | reference |
|---|---|
| Section | protocol timelines |
| Last verified | |
| Compiled by | Reference Desk |
Entry last verified July 2026. Dates are mainnet activation.
Bitcoin
| Upgrade | Year | Change |
|---|---|---|
| P2SH | 2012 | Enabled more complex spending conditions |
| SegWit | 2017 | Restructured transaction data, increased effective capacity |
| Taproot | 2021 | Improved efficiency and privacy for complex spending |
Bitcoin’s cadence is deliberately slow. Changes require broad consensus and are generally soft forks, preserving compatibility for nodes that do not upgrade.
Ethereum
| Upgrade | Year | Change |
|---|---|---|
| Homestead | 2016 | First production stability release |
| DAO fork | 2016 | Contentious state change; produced a permanent chain split |
| Byzantium | 2017 | Reward reduction, cryptographic precompiles |
| Constantinople | 2019 | Further reward reduction, gas repricing |
| Istanbul | 2019 | Gas repricing, interoperability precompiles |
| Berlin | 2021 | Gas cost adjustments |
| London | 2021 | Protocol-set base fee, burned rather than paid |
| The Merge | 2022 | Consensus moved from proof of work to proof of stake |
| Shanghai and Capella | 2023 | Enabled withdrawal of staked ETH |
| Dencun | 2024 | Dedicated data capacity for rollups |
The three that changed the most
London, which replaced a blind fee auction with an algorithmic base fee and introduced supply reduction proportional to usage.
The Merge, which cut energy consumption by more than 99 percent and changed the security model entirely, executed without a chain halt or a split.
Dencun, which priced rollup data in its own market and reduced layer 2 costs by a large multiple.
The pattern
Upgrades arrive later than announced, consistently, across every network.
The reliable indicators of a real date are testnet activation and client release notes. Roadmap announcements report the optimistic version at every stage.
What upgrades mean for holders
Usually nothing. Infrastructure handles it and users take no action.
Where action is required, wallets and venues announce it in advance. Venues typically suspend deposits and withdrawals for a short window around activation, and those notices are published by platforms including exchanges quoting a direct fiat pair.
Reading one notice is the entire preparation an ordinary holder needs.
Figures in this entry were correct on the date shown. Spotted something out of date?Send a correction and the entry gets updated.