> ## 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.

# Ecotone

> Hardfork registry entry for the Ecotone network upgrade, which adopted EIP-4844 blobs for data availability.

<Info>
  **Normative spec:** the [Ecotone specification](https://specs.optimism.io/protocol/ecotone/overview.html)
  is the canonical definition of this upgrade. This page records activation data
  and operational pointers; it does not restate the spec.
</Info>

Ecotone brought Ethereum's Dencun upgrade to the OP Stack and adopted
[EIP-4844](https://eips.ethereum.org/EIPS/eip-4844) blobs for data
availability, dramatically reducing L1 data costs.

|                                         |                                                                                       |
| --------------------------------------- | ------------------------------------------------------------------------------------- |
| Status                                  | Active                                                                                |
| Governing spec                          | [specs.optimism.io](https://specs.optimism.io/protocol/ecotone/overview.html)         |
| Governance approval                     | [proposal](https://gov.optimism.io/t/upgrade-proposal-5-ecotone-network-upgrade/7669) |
| Mainnet activation (superchain default) | Thu, 14 Mar 2024 00:00:01 UTC (`1710374401`)                                          |
| Sepolia activation (superchain default) | Wed, 21 Feb 2024 17:00:00 UTC (`1708534800`)                                          |

## What changed

Per the [spec overview](https://specs.optimism.io/protocol/ecotone/overview.html):

* Cancun EIPs on L2: [EIP-1153](https://eips.ethereum.org/EIPS/eip-1153)
  (transient storage), [EIP-4844](https://eips.ethereum.org/EIPS/eip-4844)
  (with blob transactions disabled on L2),
  [EIP-4788](https://eips.ethereum.org/EIPS/eip-4788) (L1 beacon block root
  embedded into L2), [EIP-5656](https://eips.ethereum.org/EIPS/eip-5656)
  (`MCOPY`), [EIP-6780](https://eips.ethereum.org/EIPS/eip-6780)
  (`SELFDESTRUCT` only in same transaction), and
  [EIP-7516](https://eips.ethereum.org/EIPS/eip-7516) (`BLOBBASEFEE`, always
  pushing 1 on L2).
* Consensus layer: blob data availability in the L1 data-retrieval stage and
  in L1 data fee computation.
* Auto-upgrade and extension of the `L1Block` (L1 attributes) predeploy.