Dear Celo Community,
Our initial proposal to transition Celo from an L1 to an Ethereum L2 was an ambitious mission—one that went beyond technical execution. It was a declaration of our belief in Ethereum’s future, the power of rollups and the L2-centric scaling roadmap, and the strength of a decentralized community to drive real innovation.
Now, after months of relentless engineering, deep community collaboration, and rigorous testnet iterations, we are thrilled to share a milestone that defines the next chapter for Celo:
Celo L2 Mainnet Activation Date: March 26, 2025, 3:00 AM UTC
Hardfork Block Height: 31056500
At this time, the Celo Layer 1 client will stop syncing and the Layer 2 client will take over. If you haven’t yet upgraded your full node on one of Celo’s testnets, now is the time to do so.
Built on OP Stack, secured by Ethereum with EigenDA providing data availability, our network is now a highly scalable, low-cost Layer 2, fully aligned with Ethereum’s L2-centric vision.
This is not just an upgrade. It is a return home.
Welcome to a new era of Celo.
The Road Back to Ethereum
When we first envisioned this transition, we knew it wouldn’t be easy. Taking an independent blockchain and fully integrating it into an Ethereum L2 meant reworking core aspects of the network’s architecture, systems, and structure—while still preserving the state of the network and optimizing the elements that drive Celo’s mission of prosperity for all.
Rather than launching a new network and requiring users and dapp developers to migrate over themselves, we made the conscious and difficult decision of upgrading the network via a hardfork. This required meticulous planning and implementation to ensure a smooth transition without compromising the integrity or functionality of the network.
We lightheartedly refer to this hardfork as a hard hardfork 
Though it was a significant undertaking for the core team, the end result is an upgrade that will be seamless for most of Celo’s users and developers.
The majority of the engineering work involved a complete client rewrite to a new OP Stack and EigenDA-based client—one that maintains backward compatibility with Celo’s unique and differentiated features while also eliminating technical debt. This rewrite results in a number of benefits including:
- Minimal disruption – Only full nodes need to upgrade, ensuring a smooth transition for the network while remaining transparent to users and developers building smart contracts.
- Faster transactions – We’ve lowered the blocktime from 5 seconds to 1 second, lowering the time users need to wait to see their transactions confirmed.
- Preservation of network history – The chain’s full history and block height remain intact, avoiding the need for a regenesis, enabling a smoother transition for users looking to reference past transactions.
- Tech debt reduction – This work eliminated a diff of 365,000 lines of code between the Celo L1 client and geth. This reduction will make Celo significantly more agile, setting us up for more innovation in the future.
- Trustless upgrade – Node operators can upgrade from one client to the other without resyncing. Instead, they can trustlessly migrate their chain data from the format that the Layer 1 client uses to the format that the Layer 2 client expects.
With the upgrade, the canonical version of CELO will exist both on the Celo network and on Ethereum connected via the native bridge. This will allow the CELO asset to have a larger presence in the broader Ethereum ecosystem.
Throughout this process, we stayed focused on the core principles that brought us here:
- Security & Decentralization – By aligning with Ethereum’s L2-centric roadmap, we ensure that our network is not only faster, but fundamentally more secure.
- Scalability Without Compromise – OP Stack provides an efficient, developer-friendly foundation, while EigenDA enables high-throughput, cost-effective data availability.
- A Thriving Ethereum Ecosystem – By becoming a fully integrated Ethereum L2, we strengthen our alignment with the largest and most decentralized smart contract ecosystem. This transition unlocks greater composability and enhanced developer tooling, making it easier than ever for builders and users to thrive.
- Contributing to the Superchain – After the hardfork, Celo will start paying a rev share from its sequencer fees contributing to the Superchain’s success.
Our testnet upgrades—concluding in the final, non-contentious Baklava testnet deployment, where all validators successfully upgraded to the latest L1 node—proved that this transition was not only possible, but also ready for mainnet.
Now, it’s time for Celo L2. What’s Next?
With mainnet activation imminent, our focus now shifts to:
- Ecosystem Readiness – We are working with ecosystem partners, dApps, and tooling providers to ensure a seamless transition. As part of this effort, we’ll be hosting weekly community calls to answer any questions and help teams prepare for launch.
- Preparing for Stage 1 – Over the next few months, we’ll be enhancing our fraud-proof systems, refining user exit mechanisms, and strengthening governance structures, ensuring our network operates with the highest levels of security and decentralization.
A Thank You to the Community
This transition would not have been possible without you. The engineers who architected this migration, the validators who secured our network, the developers who stress-tested our testnets, and the community members who supported every step—this belongs to all of us.
The future is here. And it starts now—within Ethereum.
The cLabs Team