> ## Documentation Index > Fetch the complete documentation index at: https://docs.optimism.io/llms.txt > Use this file to discover all available pages before exploring further. # Network upgrades > The hardfork registry — activation times, governing specs, and minimum component versions for every OP Stack network upgrade. export const NormativeSpec = ({what, title, href, note}) => Normative spec: {what} is normatively defined in the{" "} {title}. {note} ; This page is the index of the **hardfork registry**: every OP Stack hardfork has one permanent page recording its activation timestamps, governing specification, governance approval, and minimum component versions. Governance-approved [contract upgrades](#contract-upgrades) that carry no hardfork are listed separately below. Network upgrade names after Bedrock follow a geology theme based on the next letter of the English alphabet. The table below is generated from the registry pages' structured frontmatter and validated against the [superchain-registry](https://github.com/ethereum-optimism/superchain-registry) — it is never hand-edited. See [How this registry is maintained](#how-this-registry-is-maintained). ## Activations Network upgrades activate by L2 block timestamp. Failing to upgrade your OP Stack software before the activation timestamp causes a chain divergence, and you will need to resync the chain. Operator action items for each upgrade are published in [Notices](/notices). | Hardfork | Status | [Mainnet activation](https://github.com/ethereum-optimism/superchain-registry/blob/main/superchain/configs/mainnet/superchain.toml) | [Sepolia activation](https://github.com/ethereum-optimism/superchain-registry/blob/main/superchain/configs/sepolia/superchain.toml) | | ------------------------------------------------- | -------------- | ----------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------- | | [Lagoon](/op-stack/protocol/hardforks/lagoon) | In development | Not scheduled | Not scheduled | | [Karst](/op-stack/protocol/hardforks/karst) | Active | Wed, 08 Jul 2026 16:00:01 UTC (`1783526401`) | Wed, 17 Jun 2026 16:00:01 UTC (`1781712001`) | | [Jovian](/op-stack/protocol/hardforks/jovian) | Active | Tue, 02 Dec 2025 16:00:01 UTC (`1764691201`) | Wed, 19 Nov 2025 16:00:01 UTC (`1763568001`) | | [Isthmus](/op-stack/protocol/hardforks/isthmus) | Active | Fri, 09 May 2025 16:00:01 UTC (`1746806401`) | Thu, 17 Apr 2025 16:00:00 UTC (`1744905600`) | | [Holocene](/op-stack/protocol/hardforks/holocene) | Active | Thu, 09 Jan 2025 18:00:01 UTC (`1736445601`) | Tue, 26 Nov 2024 15:00:00 UTC (`1732633200`) | | [Granite](/op-stack/protocol/hardforks/granite) | Active | Wed, 11 Sep 2024 16:00:01 UTC (`1726070401`) | Mon, 12 Aug 2024 16:00:00 UTC (`1723478400`) | | [Fjord](/op-stack/protocol/hardforks/fjord) | Active | Wed, 10 Jul 2024 16:00:01 UTC (`1720627201`) | Wed, 29 May 2024 16:00:00 UTC (`1716998400`) | | [Ecotone](/op-stack/protocol/hardforks/ecotone) | Active | Thu, 14 Mar 2024 00:00:01 UTC (`1710374401`) | Wed, 21 Feb 2024 17:00:00 UTC (`1708534800`) | | [Delta](/op-stack/protocol/hardforks/delta) | Active | Thu, 22 Feb 2024 00:00:00 UTC (`1708560000`) | Fri, 22 Dec 2023 00:00:00 UTC (`1703203200`) | | [Canyon](/op-stack/protocol/hardforks/canyon) | Active | Thu, 11 Jan 2024 17:00:01 UTC (`1704992401`) | Tue, 14 Nov 2023 17:00:00 UTC (`1699981200`) | | [Regolith](/op-stack/protocol/hardforks/regolith) | Active | Genesis / at Bedrock | Genesis / at Bedrock | Activation timestamps are the superchain-wide defaults from the [superchain-registry](https://github.com/ethereum-optimism/superchain-registry). Timestamps are the canonical activation mechanism — block heights differ per chain, so no block numbers are listed. Individual chains outside those defaults set their own activation times in their chain config. All of the above build on **Bedrock**, the [governance-approved](https://gov.optimism.io/t/final-upgrade-1-bedrock-protocol-upgrade-v2/5548) 2023 re-genesis of OP Mainnet at block `105235063` (L2 timestamp `1686068903`) that the hardfork series starts from. Sepolia OP Stack chains launched on Bedrock directly. ## Contract upgrades Not every governance-approved upgrade is a hardfork: hardforks activate by L2 block timestamp on every chain, while contract upgrades ship as [op-contracts releases](/releases/op-contracts) and are executed on each chain's L1 contracts after governance approval. Contract-only upgrades have no activation timestamp, so they do not get hardfork registry pages — their permanent record is the op-contracts release history and the operator notice. | Upgrade | What it shipped | Operator notice | op-contracts release | | ----------- | ----------------------------------------------------------------------------------------------------------------- | -------------------------------------- | ---------------------------------- | | Upgrade 18 | Cannon + Kona game type, Custom Gas Token v2, creator-pattern dispute game refactor | [Notice](/notices/archive/upgrade-18) | [`v6.0.0`](/releases/op-contracts) | | Upgrade 16a | Maintenance release superseding Upgrade 16 (removes unused interop withdrawal-proving code, adds feature toggles) | [Notice](/notices/archive/upgrade-16a) | [`v4.1.0`](/releases/op-contracts) | | Upgrade 16 | Interop-ready `OptimismPortal`, Stage 1 updates, Go 1.23 support in Cannon | [Notice](/notices/archive/upgrade-16) | [`v4.0.0`](/releases/op-contracts) | | Upgrade 14 | Multithreaded 64-bit Cannon (MT-Cannon) and Isthmus L1 contracts | [Notice](/notices/archive/upgrade-14) | [`v3.0.0`](/releases/op-contracts) | | Upgrade 13 | OP Contracts Manager (OPCM) and incident response improvements | [Notice](/notices/archive/upgrade-13) | [`v2.0.0`](/releases/op-contracts) | Hardfork-carrying upgrades (for example Upgrade 15 / Isthmus, Upgrade 17 / Jovian, Upgrade 19 / Karst) are listed in the [activations table](#activations) above and link to their notices from their registry pages. ## Upgrade process Network upgrades follow this general process in which the features included in the upgrade are put into a release version cut from the `develop` branch and then the software is deployed on production networks. "Baking" on a network means the node software has been deployed and is live. Engineers take this time to observe the behavior of the software on production networks. Node Software Release Timeline * `Devnet Upgrade Notice Period` is for core developers to upgrade the node software on an internal devnet prior to the activation timestamp. * `Upgrade Activates on Devnet` * `Baking on Devnet` * `Testnet Upgrade Notice Period` is to allow testnet node operators to upgrade the node software on testnet prior to the activation timestamp. * `Upgrade Activates on Testnet` * `Baking on Testnet` * `Governance Voting Review Period` is when Optimism governance reviews proposals, including network upgrade proposals. * `Governance Voting Period` is when Optimism governance votes on proposals. * `Veto Period` is when the Citizens' House of the governance system can veto a protocol upgrade that has been approved by the Token House. * `Cut Mainnet Release` * `Mainnet Upgrade Notice Period` is to allow mainnet node operators to upgrade the node software on mainnet prior to the activation timestamp. * `Upgrade Activated` ## How this registry is maintained Each hardfork page keeps its machine-readable facts (lifecycle, activation timestamps, spec link, minimum component versions) in structured frontmatter. `scripts/generate-hardforks.ts` validates that data against the superchain-registry and renders the activation tables — a frontmatter edit followed by regeneration is the only way to change an activation row. The schema is documented in [`scripts/hardfork-registry.md`](https://github.com/ethereum-optimism/optimism/blob/develop/docs/public-docs/scripts/hardfork-registry.md).