# Changelog

This page lists Espresso network releases in reverse-chronological order. For live network details (endpoints, contract addresses, container images), see [Networks](/network/network/networks.md).

## Proof of Stake (Mainnet 1) - March 2026

Activated permissionless validator participation on the Espresso Network through delegated proof-of-stake. Previously deployed on Decaf testnet in April 2025.

## Mainnet 1 (testnet release) - April 2025

Upgraded the Espresso Network to support permissionless participation through delegated proof-of-stake. The upgrade went live on Decaf testnet on April 18, 2025; Ethereum mainnet upgrade followed March 4, 2026.

* Permissionless validator set (top 100 by delegated stake per epoch)
* New stake table and ESP token contracts
* API moves from `v0` to `v1`
* See [Chain Migration Guide](/network/developer/rollup-developers/nitro/rollup-migration-guide.md) for integration changes

## Mainnet 0 - October 2024

First production release of the Espresso Network. Initial operator set: 20 node operators running 100 nodes. Initial block size 1 MB with planned scaling to 5 MB. Target confirmation latency \~8 seconds at launch.

## Decaf Testnet - September 2024

Launched Decaf as Espresso's persistent testnet alongside the upcoming Mainnet release. Expanded operator set to 24 operators running 100 geographically distributed nodes.

## Cappuccino Testnet - May 2024

Onboarded 10 operators running 100 geographically distributed nodes. Tiramisu DA layer upgraded with VID support. Added Arbitrum Nitro fraud-proof support, enabling Arbitrum chains to run fully productized on Espresso. *Deprecated by Decaf.*

## Gibraltar Testnet - January 2024

First integration with Arbitrum Nitro, along with progress on [Savoiardi](https://hackmd.io/@EspressoSystems/HotShot-and-Tiramisu#Part-III-Tiramisu-The-Three-Layered-Espresso-DA) (a VID implementation forming the backbone of the Tiramisu DA solution). First testnet run by external node operators in collaboration with Blockdaemon. *Deprecated.*

## Cortado Testnet - September 2023

First integration with the OP Stack, resulting from Espresso's work on [a leader election interface for the OP Stack](https://github.com/ethereum-optimism/optimism/issues/6437). Public testnet deployed with two chains of different stacks: an OP Stack chain (Vienna, by Caldera) and a Polygon zkEVM chain. *Deprecated.*

## Doppio Testnet - July 2023

Second testnet of the Espresso Network. Includes integrations with both a minimal chain example and the Polygon zkEVM stack. [Announcement](https://medium.com/@espressosys/releasing-the-espresso-sequencer-testnet-ii-doppio-bcc46c315c30) · [Public testnet announcement](https://medium.com/@espressosys/opening-the-doppio-testnet-to-the-public-904680bd07b1). *Deprecated.*

## Americano Testnet - November 2022

First testnet of Espresso. [Announcement](https://medium.com/@espressosys/releasing-espresso-testnet-1-americano-45d6c44d2a5c). *Deprecated.*


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