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Target date: Dec. 3 mainnet, pending final confirmations.
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Testnets: Holesky (Oct. 1), Sepolia (Oct. 14), Hoodi (Oct. 28).
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Key features: Peer Data Availability Sampling, gas limit to 150M, Verkle Trees, EVM performance boosts.
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Throughput: Devs expect blob capacity to roughly double within two weeks post-fork.
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Security: Four-week audit contest with up to $2M in rewards. Next major fork: Glamsterdam (2026).
Timeline and activation plan
Developers shared on ACDC #165 that Fusaka is slated for Dec. 3 on mainnet, following staged activations on Holesky (Oct. 1), Sepolia (Oct. 14), and Hoodi (Oct. 28). Exact timestamps/epochs will be reconfirmed in the coming days.
What’s inside Fusaka
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Peer Data Availability Sampling (Peer DAS): Lets validators verify large “blob” datasets by sampling from peers instead of downloading them in full—cutting bandwidth while preserving security.
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Gas limit increase (30M → 150M): A 5× lift intended to support higher transactional throughput.
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Verkle Trees: More compact state commitments enable smaller proofs and leaner state growth, paving the way for future light-client improvements.
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EVM perf upgrades: Interpreter and opcode optimizations to speed up contract execution.
Why it matters
The combo of Peer DAS + larger gas limit targets a tangible step-up in capacity and UX—especially for rollups posting blobs—while Verkle Trees advance the roadmap to a more scalable, light-client-friendly Ethereum. Core contributors expect blob bandwidth to roughly double within two weeks after activation, supporting cheaper data for L2s.
Testing, audits, and risk controls
Alongside the testnet cadence, the Ethereum Foundation kicked off a four-week audit competition (up to $2M in bounties) to surface client and spec issues before mainnet. Split-phase activations and client diversity remain central to limiting correlated failures.
What’s next: Glamsterdam (2026)
Post-Fusaka, core devs expect Glamsterdam in 2026, likely emphasizing EOF (EVM Object Format), further scalability, and potential faster block times—continuing the roadmap toward higher throughput and better developer ergonomics.
