Ethereum\u2019s next major network upgrade, Fusaka, has officially gone live on the Sepolia testnet, a key step toward its full mainnet rollout expected in December 2025. <\/p>\n\n\n\n
The activation marks the second stage in Ethereum\u2019s multi-phase testing plan, which will determine the network\u2019s readiness for what developers describe as one of the most technically ambitious updates since The Merge.<\/p>\n\n\n\n
The Fusaka upgrade was first tested on the Holesky testnet earlier this month, with developers now shifting focus to Sepolia to evaluate real-world performance under heavier transaction loads. The final round of testing is scheduled for the Hoodi testnet later in October. If no critical issues arise, Fusaka will be activated on the Ethereum mainnet on December 3, 2025.<\/p>\n\n\n\n
At the core of Fusaka is Peer Data Availability Sampling (PeerDAS), a new mechanism designed to make Ethereum more efficient and scalable. Instead of requiring validators to download and verify entire data sets, PeerDAS allows them to verify portions of data shared by peers. This reduces bandwidth use, lowers storage requirements, and helps make node operation less resource-intensive.<\/p>\n\n\n\n
Developers have also proposed increasing Ethereum\u2019s block gas limit to 60 million, allowing for more transactions and complex smart contracts to be processed in each block. These improvements aim to enhance throughput, reduce network congestion, and lower transaction costs while maintaining Ethereum\u2019s decentralization and security standards.<\/p>\n\n\n\n
The Fusaka release builds on progress from earlier upgrades such as Pectra, which introduced features that allowed externally owned accounts (EOAs) to act more like smart contracts and expanded validator capabilities. Fusaka continues that trajectory, focusing primarily on network scalability and improved coordination between the Ethereum main chain and layer-2 rollups