Ethereum’s much-anticipated Fusaka upgrade is officially rolling out across testnets, beginning with Holesky on October 1, 2025, followed by Sepolia on October 14, and concluding with Hoodi on October 28. The phased activation marks a significant step in Ethereum’s long-term scaling roadmap, bringing PeerDAS & other key improvements to life.
The Testnet Activation Timeline
The Fusaka upgrade will follow a staggered release schedule across Ethereum’s major testnets:
- Holesky – October 1, 2025, at slot 5,283,840
- Sepolia – October 14, 2025, at slot 8,724,480
- Hoodi – October 28, 2025, at slot 1,622,016
Each activation ensures proper testing & stability before developers finalize a mainnet launch date. This step-by-step rollout also gives node operators, stakers, and tooling providers time to update clients & validate stability.
Why Fusaka Matters
Fusaka introduces PeerDAS (EIP-7594), enabling Ethereum to scale blob throughput without compromising decentralization or security. With layer 2 rollups frequently hitting the current blob limits, PeerDAS provides the path to cheaper fees & higher capacity.
Alongside PeerDAS, Fusaka brings:
- Blob Parameter Only (BPO) forks to gradually increase blob limits from 9 per block up to 21.
- Gas optimizations like ModExp fixes & a 60M default gas limit (EIP-7935).
- User experience upgrades, including support for secp256r1 hardware wallets & the CLZ opcode for ZK scaling.
These changes make Fusaka one of the most consequential testnet upgrades since Dencun, directly impacting both L1 performance & L2 affordability.
The Last Ride for Holesky
While Holesky will be the first to activate Fusaka, it will also be the last upgrade for this testnet. Ethereum core developers have already announced that Holesky will be shut down shortly after Fusaka’s deployment.
For developers & validators, this means Holesky will serve as a final proving ground for Fusaka before Sepolia & Hoodi take over the long-term role of active testing environments.
The Fusaka testnet journey starts with Holesky on October 1 and ends with Hoodi on October 28, cementing its place as the upgrade that ushers Ethereum into the next phase of scalability. With PeerDAS, BPO forks, and UX-focused enhancements, Fusaka sets the stage for lower fees, higher capacity, and a smoother experience across the Ethereum ecosystem.
If you find any issues in this blog or notice any missing information, please feel free to reach out at yash@etherworld.co for clarifications or updates.
Related Articles
- Ethereum Launches $2 Million Fusaka Audit Contest to Fortify Protocol Security
- Ethereum Developers Announce "The Weld" Repository Merger
- Ethereum Developers Target September 22 for Holesky Client Releases
- Ethereum Developers Face Blockers in Shadowfork Testing Ahead of Fusaka
- A New Playbook for Ethereum: Fusaka Rethinks Testnet & Mainnet Schedules
Disclaimer: The information contained in this website is for general informational purposes only. The content provided on this website, including articles, blog posts, opinions, & analysis related to blockchain technology & cryptocurrencies, is not intended as financial or investment advice. The website & its content should not be relied upon for making financial decisions. Read full disclaimer & privacy policy.
For Press Releases, project updates & guest posts publishing with us, email contact@etherworld.co.
Subscribe to EtherWorld YouTube channel for ELI5 content.
Share if you like the content. Donate at avarch.eth.
You've something to share with the blockchain community, join us on Discord!
