The people shaping Ethereum’s September 2026 Fusaka upgrade

The Fusaka upgrade, which activated on mainnet on December 3, 2025, uses PeerDAS to increase data availability capacity for Layer 2 rollups. This protocol, defined in EIP-7594, uses erasure coding to divide blob data into 128 columns. Each node subscribes to 8 randomly chosen subnets to receive 1/8th of the original data. Because the system uses Reed-Solomon style erasure coding, any 50% of the columns can reconstruct the full data. Nodes use KZG commitments to verify these samples against the block commitment. Each node maintains a unique randomly generated ID to determine its random set of subnets. This design allows nodes to verify data by sampling small portions instead of downloading entire data sets.

Ethereum manages blob growth through Blob Parameter Only (BPO) forks. These config-only upgrades change blob counts without needing coordinated node software updates. BPO1 increases the target and maximum blobs to 10 and 15, while BPO2 raises these to 14 and 21. Will these automated shifts cause network instability during high traffic? You might wonder if these changes affect your own node.

Scaling execution and consensus

The Scale track, led by Ansgar Dietrichs, Marius van der Wijden, and Raul Kripalani, coordinated the increase of the default gas limit to 60 million following previous increases from 30 million to 36 million in February 2025 and to 45 million later that year. EIP-7825 imposes a 16,777,216 gas cap per transaction to prevent single transactions from dominating blocks. EIP-7934 also sets a 10 MiB ceiling on RLP-encoded execution block sizes to ensure clean propagation. EIP-7825 and EIP-7935 work to accommodate the higher gas limit through transaction gas limit caps.

EIP-7732 introduces Enshrined Proposer-Builder Separation (ePBS) to decouple block proposing from block building. This EIP removes the execution payload field from the beacon block and replaces it with a signed commitment from a builder. Builders must stake in the beacon chain to participate. Validators in the Payload Timeliness Committee attest to whether the builder revealed the correct payload and if the blob data remains available. EIP-7883 and EIP-7823 optimize the MODEXP precompile by increasing gas costs and capping input numbers at 8192 bits. These changes ensure that resource-intensive cryptographic operations do not slow down block validation. EIP-7917 also makes the Beacon Chain aware of upcoming block proposers for the next epoch to enable preconfirmations.

Developer shifts and protocol stability

The Ethereum Foundation restructuring in 2025 moved execution work to independent client teams while the Foundation shifted to research and grants. This shift resulted in eight senior researchers leaving the Foundation in 2026, including Carl Beek and Julian Ma in May. The Protocol Cluster, which handles research, lost contributors across every layer it covers. The loss of institutional knowledge remains a problem. This brain drain occurred after the Pectra upgrade, which introduced EIP-7702 and raised the validator staking cap to 2,048 ETH.

The Harden L1 track, managed by Fredrik Svantes, Parithosh Jayanthi, and Thomas Thiery, handles security and network resilience. Parithosh Jayanthi’s work on devnets and testnets helped validate the 60 million gas limit through stress testing with synthetic loads. The team aims to maintain security while scaling through the next major upgrade, Glamsterdam, in the first half of 2026. The team works on censorship resistance and network resilience to protect the network properties. The current focus includes the Trillion Dollar Security Initiative led by Fredrik Svantes. The departures include Barnabe Monnot, Tim Beiko, Trent Van Epps, Alex Stokes, and the operations lead Josh. These changes in leadership follow the 2025 reorganization where Vitalik Buterin moved the Foundation toward a research-focused model. This structural shift means the Foundation focuses more on grants than direct implementation.