> ## 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.

# Lagoon

> Hardfork registry entry for the Lagoon network upgrade, which activates Superchain interop.

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

Lagoon is the upcoming hardfork that activates Superchain
[interop](/op-stack/interop/explainer). No superchain-wide activation defaults
are set in the superchain-registry yet; the first activations are being
prepared per chain — see the
[interop activation prep notice](/notices/interop-prep) for OP Sepolia and
Unichain Sepolia.

|                                         |                                                                              |
| --------------------------------------- | ---------------------------------------------------------------------------- |
| Status                                  | In development                                                               |
| Governing spec                          | [specs.optimism.io](https://specs.optimism.io/protocol/lagoon/overview.html) |
| Operator notice                         | [View notice](/notices/interop-prep)                                         |
| Mainnet activation (superchain default) | Not scheduled                                                                |
| Sepolia activation (superchain default) | Not scheduled                                                                |

## What's included

Per the [spec overview](https://specs.optimism.io/protocol/lagoon/overview.html)
(subject to change while the spec is in development):

* Interop: dependency set, cross-chain messaging, derivation, sequencer and
  verifier behavior, super roots, interop fault proofs, and the interop
  bridging contracts.
* Execution layer: post-execution transactions and sequencer-defined
  metering.