Ethereum’s highly anticipated Fusaka upgrade has been officially scheduled for December 3, 2025, following an announcement during the latest AllCoreDevs meeting. This release date marks a slight delay from the initial November timeline but sets the stage for significant improvements to the Ethereum network.
The Fusaka upgrade is primarily focused on enhancing the scalability of Ethereum, with a specific emphasis on improving data availability for Layer 2 (L2) networks. By optimizing core protocol functionality through the implementation of 11 Ethereum Improvement Proposals (EIPs), Fusaka aims to make the network faster and more cost-effective for users.
In preparation for the mainnet rollout of Fusaka, testnet upgrades on Holesky, Sepolia, and Hoodi are set to take place in October. These upgrades will help ensure a smooth transition to Fusaka and allow developers to address any potential issues before the official release date.
Additionally, two follow-on upgrades known as “blob parameter only” (BPO) upgrades are scheduled to incrementally increase the maximum number of “blobs” per block from 6 to 15 and eventually to 21. This enhancement will boost data throughput for rollups, further improving the efficiency and performance of the Ethereum network.
To support the deployment of Fusaka and enhance security measures, the Ethereum Foundation has launched a four-week audit contest offering up to $2 million in bug-bounty rewards. Independent researchers are invited to scrutinize Fusaka’s code for vulnerabilities to ensure a secure and stable network upgrade.
The Fusaka upgrade introduces a new technique called PeerDAS (Peer Data Availability Sampling) to enhance resource efficiency, data capacity, and scalability on the Ethereum network. While smart contract behavior will remain unchanged initially, Fusaka paves the way for Ethereum to achieve up to 12,000 transactions per second by 2026, a significant milestone that could revolutionize the blockchain’s capabilities.
Furthermore, Fusaka is expected to reduce gas fees for L2 projects, making Ethereum more cost-effective and faster to use. This improvement is likely to attract more DeFi platforms, on-chain games, and real-world asset protocols to the Ethereum network, thanks to its enhanced scalability and affordability.
In addition to these enhancements, Fusaka introduces stronger spam-prevention rules to deter low-value transaction flooding on the network. By optimizing data storage and laying the groundwork for future improvements, Fusaka sets the stage for a more stable and efficient Ethereum network.
With the countdown to the December mainnet deployment underway, the Ethereum community is eagerly anticipating the benefits that Fusaka will bring as the network continues to evolve towards a more scalable and robust future.