Ethereum's Fusaka Upgrade Enters Final Development Phase

Ethereum's highly anticipated Fusaka network upgrade, a significant overhaul combining the Osaka execution layer and the Fulu consensus layer, has entered its final development stage. This upgrade, scheduled to go live on December 3, 2025, aims to push Ethereum's scaling, security, and user experience into the future.

A headline feature of Fusaka is data availability sampling (PeerDAS). Currently, full nodes must store all blob data posted by Layer 2 solutions. PeerDAS will allow each node to store only a subset of blob data, enabling theoretical scaling up to 8x while keeping hardware and bandwidth requirements manageable. This is crucial for Layer 2s to post more data to Ethereum as they grow, leading to potentially smaller fees and increased efficiency.

To adapt more quickly to the evolving data needs of Layer 2s, Fusaka introduces blob parameter-only forks. These allow for increases in the target and maximum number of blobs without waiting for major network upgrades, offering greater flexibility. For instance, the target number of blobs, initially set at 3 in the Dencun upgrade and increased to 6 in Pectra, can now be adjusted more sustainably.

Additionally, EIP-7918 pins a proportional reserve price under every blob, ensuring that blob base fees are bounded by execution costs and do not spiral down to a point where they cease to function as a price signal. The preceding Pectra upgrade, slated for May 7, 2025, was intended to introduce smart accounts for improved user experience, enhance staking for institutional investors, and double the available space for L2 blobs.