What is the Ethereum L1 Fusaka upgrade
The Fusaka hardfork contains various breaking changes on the L1. See EIP-7607: Hardfork Meta - Fusaka for more info.Important dates
Fusaka activated on Ethereum Mainnet on Wednesday, December 3rd, 2025 at 21:49:11 UTC and on Ethereum Sepolia on Tuesday, October 14th, 2025 at 07:36:00 UTC; it affected Celo Mainnet and Celo Sepolia respectively. As Celo relies on Ethereum L1, node operators had to provide Fusaka-compatible L1 node access for the Celo client.The Fusaka upgrade required no changes for Celo users.
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For Node Operators
L1 Ethereum clients
L1 nodes had to be updated to a Fusaka-compatible version before the fork. The Ethereum client release list names the compatible versions.L2 Celo client
No upgrade of the Celo L2 client was required for the L1 Fusaka upgrade. The Celo client versions recommended at the time wereop-geth v2.1.2, op-node v2.1.0 and eigenda-proxy v1.8.2. For current versions see Network config.