Entries → protocol timelines
Ethereum: Timeline of Every Major Upgrade
Each named upgrade, its date, and what it actually changed. A reference rather than a narrative.
| Entry type | reference |
|---|---|
| Section | protocol timelines |
| Last verified | |
| Compiled by | Reference Desk |
Entry last verified May 2026. Dates are mainnet activation.
The upgrades
| Upgrade | Year | Principal change |
|---|---|---|
| Frontier | 2015 | Initial live network |
| Homestead | 2016 | First production-stability release |
| DAO Fork | 2016 | Contentious state change reversing an exploit; produced a permanent chain split |
| Byzantium | 2017 | Reduced block reward, added cryptographic precompiles |
| Constantinople | 2019 | Further reward reduction, gas cost changes |
| Istanbul | 2019 | Gas repricing, interoperability precompiles |
| Berlin | 2021 | Gas cost adjustments for specific operations |
| London | 2021 | EIP-1559: base fee set by protocol and burned |
| The Merge | 2022 | Consensus changed from proof of work to proof of stake |
| Shanghai and Capella | 2023 | Enabled withdrawal of staked ETH |
| Dencun | 2024 | Dedicated data capacity for rollups, substantially reducing layer 2 fees |
The three that changed the most
London, 2021. Replaced the blind fee auction with a protocol-set base fee that is burned rather than paid to validators. Improved fee predictability and introduced a supply reduction proportional to network usage.
The Merge, 2022. Replaced mining with staking. Energy consumption fell by more than 99 percent. Issuance fell substantially. The execution was notable for producing no chain halt and no split.
Dencun, 2024. Introduced data capacity priced separately from ordinary transactions, specifically for rollups. Layer 2 transaction costs fell by a large multiple and decoupled from mainnet congestion.
The DAO fork
In 2016, an exploit drained a large contract. The community chose to execute a state change reversing it. A minority continued on the original chain, which persists as a separate network.
The event is the clearest demonstration that immutability is a social property enforced by node operators rather than a mechanical one.
Post-Merge issuance
Issuance is now a function of total staked ETH rather than a fixed block reward. Net supply change depends on the balance between issuance and the base fee burned, and has been negative during periods of high activity.
This is a mechanical consequence of the fee design rather than a monetary policy decision, and it varies with usage.
Staking parameters
| Parameter | Value |
|---|---|
| Stake per validator | 32 ETH |
| Slot interval | 12 seconds |
| Epoch | 32 slots, approximately 6.4 minutes |
| Finality | Typically two epochs, approximately 13 minutes |
| Withdrawal | Enabled since 2023, subject to an exit queue |
What comes next
The publicly stated development direction includes further data capacity expansion for rollups and changes to state storage aimed at reducing node requirements.
Roadmap items do not have reliable dates. The specification repository and client release notes are the accurate source; coverage of roadmap announcements consistently reports the optimistic version.
Figures in this entry were correct on the date shown. Spotted something out of date?Send a correction and the entry gets updated.