What happens to the Ethereum mainnet after Fusaka upgrade

Ethereum (ETH) has rolled out three major network upgrades since The Merge in September 2022 — Shanghai, Dencun, and Pectra — and is now counting down the final steps to bring the next upgrade, Fusaka, live on mainnet.
Developers deployed Fusaka to its second public test network, Sepolia, on October 14. According to the timeline, next on the schedule is the upgrade’s activation on the final testnet, Hoodi, on October 28. Once testing wraps up successfully, the upgrade is expected to go live on the mainnet on December 3.
Fusaka & BPO mainnet activation schedule. Source: Ethereum Public Notes
Looking back, Ethereum has steadily evolved after its PoS transition: Shanghai in September 2022 allowed staked ETH withdrawals; Dencun in March 2024 introduced proto-danksharding (blobs) to streamline Layer-2 data. Finally, Pectra in May 2025 focused on validator flexibility.
Fusaka, named the star Fulu and the Devcon V host city Osaka, is set to unlock new levels of scalability for Ethereum, introducing improvements in data handling and network throughput.
How Ethereum mainnet changes with Fusaka
This major hard fork introduces 13 EIPs (Ethereum Improvement Proposals) to the network. Of these, the most notable — EIP-7594 or PeerDAS (Peer Data Availability Sampling) and EIP-7892 or Blob Parameter Only (BPO) — are both pivotal for the network’s next phase of scaling.
PeerDAS allows validators to verify large datasets without downloading or storing full blocks. Validators instead sample small portions from peers to probabilistically confirm data availability. Paired with Verkle Trees, which streamline and compress data proofs, the network can process more rollup data (blobs) per block, reduce Layer 2 fees, and maintain security and decentralization.
Alongside this, the upgrade is expected to increase Ethereum’s gas limit to 60 million units, nearly a 33% jump from the current 45 million, and handle more transactions without compromising stability or contract compatibility.
After the main activation, Ethereum will roll out two BPO upgrades to gradually boost blob throughput. BPO1 lifts the per-block blob target and maximum to 10 and 15, respectively. Then BPO2 later pushes these to 14 and 21.
Finally, following Fusaka, Ethereum will advance toward its next upgrade—Glamsterdam—introducing key proposals, such as enshrined proposer-builder separation (ePBS) and others.