Ethereum on Wednesday enabled the long-awaited “Fusaka” upgrade, marking the blockchain’s second major code change in 2025.
This update is designed to help Ethereum handle increasingly large batches of transactions from the Layer 2 network anchored on top of Ethereum.
The Fusaka upgrade, also known as a “hard fork,” started at 21:49 UTC and is expected to be completed within about 15 minutes, after which developers will know whether the changes were implemented smoothly. Many core developers gathered on the EthStaker livestream to celebrate this occasion.
Fusaka (combining the names Fulu + OSAKA) bundles two parallel hard forks on Ethereum. One is the consensus layer and the other is the execution layer. The former is where transactions and smart contracts are executed, and the payment layer is where these transactions are verified, finalized, and secured.
At the heart of the upgrade is PeerDAS, a system that allows validators to check small slices of data rather than entire “blobs”, reducing both cost and computational load for validators and Layer 2 networks.
Currently, Layer 2 sends transaction data to Ethereum in the form of BLOBs, which validators must fully download and verify. This process causes congestion and slows down the network. PeerDAS changes this by allowing validators to validate only a small portion of a blob’s data. This speeds up the verification process and reduces gas fees associated with processing.
This upgrade is expected to lower the barrier for small or new validator operators by reducing the resources required to run a small number of validators beyond layer 2. Still, Ethereum developers note that institutions operating large node fleets, such as staking pools, will not see the same level of savings.
“We are only increasing blobs slowly to allow the network to safely handle the increase in throughput, so it will take several months for the improvements to be fully implemented,” Marius van der Weyden, a core developer at the Ethereum Foundation, told CoinDesk via Telegram.
Ethereum developers moved quickly to ship upgrades this year as the ecosystem grapples with a reputation for slow or delayed deployments. The goal was to make a series of small improvements now while preparing for more ambitious changes down the road.
“PeerDAS was so important that during the initial development of the Fusaka upgrade, features that risked delaying the fork, such as features that required more research or features with high complexity, were deprioritized and removed from scope,” said Gabriel Trintinalia, Ethereum Core Developer and Engineer at Consensys. “The Fusaka upgrade shows that Ethereum is serious about making its mainnet faster.”
Traditional financial institutions (TradFi) are taking notice as well. Last month, Fidelity Digital Assets published a report describing Fusaka as a decisive step towards a more strategically aligned and economically coherent roadmap for Ethereum.
What else is there in Fusaka?
Although Fusaka’s main focus is on PeerDAS, there are 12 other Ethereum Improvement Proposals (EIPs) built into the package, most of which improve the developer experience and network health. These include:
- EIP-7642: Remove old and unused fields from Ethereum network messages to simplify and clean up the protocol.
- EIP-7823: Place a cap on the size of certain math operations to avoid overloading the network.
- EIP-7825: Setting a cap on the size of a single transaction prevents it from containing very large and resource-intensive transactions.
- EIP-7883: Increase the cost of certain types of math operations with gas to prevent heavy calculations from unduly taxing the network.
- EIP-7892: A future upgrade will allow you to change only BLOB-related settings without touching the rest of the protocol, making BLOB tuning safer and easier.
- EIP-7910: Add new API methods to make it easier for software to see what configurations or rules a node is using.
- EIP-7917: Make the process of predicting who will propose the next block more transparent and reliable.
- EIP-7918: Ensure BLOB data charges match actual processing costs to prevent extreme price fluctuations.
- EIP-7934: Add strict size limits to certain block data to prevent too large blocks from slowing down the chain.
- EIP-7935: Increase the default block gas limit to 60 million to allow the network to accommodate more computations in each block.
- EIP-7939: Add simple new instructions to smart contracts to improve efficiency of some calculations.
- EIP-7951: Add built-in support for widely used cryptographic signature types.
As for what will happen next, developers are already thinking about the network’s next big upgrade, Gramsterdam, but nothing has been finalized yet as to when it will happen or what it will include.
Read more: Ethereum’s Fusaka upgrade could reduce node costs and ease adoption
