Dear Celo community,
Today marks an important milestone for the Celo ecosystem.We are excited to share that the Jello Hardfork has been successfully activated on Celo Mainnet, bringing OP Succinct Lite and ZK-powered fault proofs into full production.
With this upgrade, Celo becomes the first chain to implement OP Succinct Lite on Mainnet and the first chain to launch a fully auditable DA bridge for EigenDA, delivering faster, more secure verification and advancing Celo’s evolution as a high-performance Layer 2 built for real-world payments.
This achievement reflects nearly a year of focused engineering effort, shaped through close collaboration with the EigenDA and Succinct teams as we worked together to bring this milestone to life.
OP Succinct Lite Is Now Live
With Jello now active on Mainnet, the following capabilities are officially enabled across the network:
- OP Succinct Lite as the operational fault-proof system
- ZK-powered, non-interactive proofs for efficient dispute resolution
- DA bridge leveraging zk-proofs to provide strong EigenDA data availability guarantees
- New Rust-based Celo-compatible EVM client used for constructing proofs with Succinct’s SP1
- Introduction of challengers: independent entities monitoring proposer behavior
- Alignment with L2 Beat criteria for decentralized fault-proof readiness in the “Validiums and Optimiums” category
This upgrade strengthens Celo’s network security and integrity while maintaining its commitment to low-fee, mobile-friendly transaction experiences. This also marks Celo’s first use of zk-based transaction proving, paving the way for faster and more secure interoperability with Ethereum.
Introducing Celo’s Challenger Set
A major part of today’s activation is the introduction of challengers, third-party actors who continuously verify proposer behavior and submit challenges when necessary.
Celo’s initial challenger set includes:
- Five independent challengers from across the Celo ecosystem
- One challenger operated by cLabs
This diverse group plays a critical role in monitoring the sequencer, detecting faulty state submissions, and enforcing the rollup’s security guarantees. Their participation increases censorship resistance, strengthens decentralization, and ensures that Celo’s new proof system operates with robust, real-world oversight from day one.
As the network evolves, additional challengers can be onboarded to expand resilience and decentralization, and eventually, the set will become fully permissionless.
A Seamless Upgrade
As expected, the upgrade process completed smoothly and required no action from full nodes, developers, or ecosystem partners.
- All applications and tooling remain fully backward compatible
- The activation occurred through L1 smart-contract updates governed by the Celo Security Council
- Network availability and performance remained uninterrupted throughout the transition
This smooth execution reflects the rigor of the Eclair and Celo Sepolia testing phases and the strength of Celo’s modular upgrade approach.
How We Got Here
The Mainnet rollout follows extensive testing across multiple phases. Together with partners at Succinct Labs and EigenDA, the cLabs team completed:
- Porting of Celo core features like Token Duality and Fee Abstraction to Celo-Kona, a new Rust based EVM based on the kona project
- Integrating EigenDA’s Hokulea into OP Succinct Lite
- Creation of testing tools for verification of the Go and Rust based implementations of the Celo protocol
- Large-scale testnet exercises simulating Mainnet conditions
- Verification of proof generation, dispute flows, and data availability interactions
- Full end-to-end testing of OP Succinct Lite within Celo’s execution pipeline
- Independent audit of Celo-Kona
- Community review of upgrade specifications and test outcomes
As with all major Celo protocol upgrades requiring L1 contract upgrades, the Celo Security Council reviewed and approved the change.
What Comes Next
With Jello live, Celo now operates with:
- ZK-driven verification
- Scalable data availability through EigenDA v2
- A hardened execution environment powered by the Optimism OP Stack
- A multi-party challenger set ensuring ongoing network integrity
This new foundation enables the next phases of Celo’s Layer 2 roadmap, including even greater throughput, better interop with Ethereum, improved finality guarantees, and a march towards stage 2 status.
Work will now expand to deepening challenger participation, enhancing monitoring infrastructure, and preparing for subsequent protocol upgrades aligned with Celo’s long-term vision for global, accessible payments.
Thank You
We want to extend our sincere thanks to the Celo community, builders, and partners for your continued support throughout the Eclair and Jello phases.
Your collaboration and feedback have been essential in reaching this milestone.
We look forward to continuing this journey together as Celo advances its mission of bringing fast, secure, and affordable onchain payments to people around the world.
The cLabs team