Can the Fusaka upgrade push Ethereum towards its final form?

Author: Mars_DeFi Source: X, @Mars_DeFi Translation: Shan Oppa, Jinse Caijing

The Fusaka upgrade of Ethereum is the latest step in its ten-year engineering plan - a plan that steadily transforms Ethereum from a fragile experiment into a global settlement platform.

To understand why the Sharding upgrade is of great significance and why the network has little choice but to push forward with such upgrades, we first need to review the development history of Ethereum.

Phase One: The Birth of Ethereum (2015-2017)

Frontier

Ethereum went live in July 2015 with the “Frontier” version. Core achievements:

• The first programmable blockchain
• Smart contracts that can be deployed in a production environment
• Gas-based fee model
• Proof of Work (PoW) consensus mechanism

The state at that time:

• No wallet application
• No Decentralized Finance (DeFi)
• Non-Fungible Tokens (NFT)
• No supporting tool ecosystem

It is only in the native experimental stage for developers. The trading price of Ethereum (ETH) fluctuates between 1-3 dollars. No one can predict what form Ethereum will grow into in the future.

Homestead 2016:

This upgrade marks a step towards the maturity of Ethereum. Core achievements:

• Improvement of Protocol Stability
• New opcodes
• More secure upgrade mechanism
• Optimized network performance

Key events of the same year:

• Decentralized Autonomous Organization Collapse
• Millions of ETH stolen
• Hard fork on Ethereum
• Ethereum and Ethereum Classic part ways

The painful lessons brought by this upgrade have made security an unshakeable principle. Audits have since become a mandatory requirement, which has slowed down the pace of innovation but has made Ethereum much stronger.

Byzantine: 2017

This is an important upgrade on the technical level of cryptocurrency, with key highlights including:

• zk-SNARKs
• Reduce ETH issuance
• Security Optimization
• Difficulty Bomb Scheduling Mechanism

Significance of the Upgrade:

• Ethereum builds a privacy protection infrastructure
• Contract execution is safer
• ETH supply is becoming scarce

Phase Two: Era of Scalability Pressure (2018-2020)

During this period, the user demand for Ethereum experienced explosive growth, arriving earlier than expected. The direct consequence was block congestion, soaring fees, and frequent application failures. Therefore, Ethereum had to respond to the challenges through efficiency upgrades.

Constantinople and Saint Petersburg: 2019

Core Optimization:

• The cost of cryptographic operations has decreased.
• Deterministic contract address (CREATE2 instruction)
• Reduction in issuance (from 3ETH per block to 2ETH)
• Gas Fee Optimization

Ironically, on the day of its launch, a security vulnerability triggered the St. Petersburg fork. This event made the Ethereum team determined: upgrades must be carried out steadily and must not be rushed.

Istanbul: 2019

Ethereum has quietly shifted its focus to Rollup. The upgrade content includes:

• Reduce data call costs
• Strengthen zk support
• Replay Protection Mechanism
• Cross-chain functionality optimization

Hidden Achievement: Rollup solutions are feasible, Ethereum begins to lay out for L2.

Muir Glacier: 2020

Ethereum has once again postponed the triggering time of the difficulty bomb. Key reasons:

• The complexity of the Proof of Stake mechanism is high
• Ethereum refuses to rush forward
• The preparation work for the merger is ongoing.

Stage Three: Decentralized Finance, Non-Fungible Tokens, and Fee Hell (2021-2022)

Ethereum has become the core ecological battlefield for Decentralized Finance (DeFi), ERC-20 tokens, Non-Fungible Tokens (NFTs), and Decentralized Autonomous Organizations (DAOs). Accompanying the growth are high Gas fees and frequent transaction failures, with only large whales able to operate smoothly.

London Upgrade: 2021

This upgrade completely reconstructs Ethereum's economic engine, with key introductions:

• Fee Burn Mechanism (EIP-1559)
• Dynamic Base Fee
• Predictable Gas Pricing Model

Long-term impact:

• During peak demand periods, ETH enters a deflationary state.
• Supply and usage rates tend to match
• Ethereum realizes congestion (turning congestion into value)

Paris Upgrade: 2022

Ethereum has accomplished a feat that no mainstream network has dared to attempt in history: replacing the Proof of Work (PoW) consensus mechanism with the Proof of Stake (PoS) during the operation of the mainnet. This event is referred to as the Merge. This bold move brings profound positive impacts to Ethereum:

• Energy consumption reduced by 99.95%
• Circulation decreased by 90%
• ETH has become a scarce capital asset

Stage Four: Rollup Era (2023-2025)

Ethereum is no longer pursuing “all-encompassing execution,” but is shifting towards “focusing on all settlements.”

Shapella: Year 2023

This upgrade has realized the unlocking of staked ETH. Core achievements:

• Staking Volume Increase
• Panic selling decreases
• The number of validators is steadily increasing.

As of now:

• About 30% of ETH is staked.
• The number of validators is close to 1 million

Dencun: 2024

The upgrade to Ethereum through EIP-4844 introduced “prototype Danksharding” (a sharding precursor scheme). It did not directly implement complete sharding but instead added a special transaction type that can carry “data blocks.” These temporarily stored Rollup data are cheaper than calling data costs and will be automatically pruned and cleaned.

Core Achievements:

• L2 transaction fees reduced by 90%
• Rollup ecosystem explosive growth
• Ethereum achieves “low cost” without changing the core architecture.

Pectra: Year 2025

This stage is the “User Experience Optimization Era” of Ethereum, making Ethereum truly valuable in practical terms. Core introduction:

• Smart Wallet Function
• Gas abstraction (no need to directly hold ETH to pay fees)
• Validator Integration
• Unification of Execution Layer and Consensus Layer

The accessibility of Ethereum has significantly improved, making it more aligned with the needs of investors.

Upcoming Fusaka Upgrade:

It should be clear that Vitalik Buterin divides the development of Ethereum into five major stages:

• Scalability: Enhance network throughput
• Anti-MEV: Defend against Maximum Extractable Value (MEV) attacks
• Stateless: Achieve statelessness
• Cleanup: Historical Data Cleanup
• Optimization: User Experience Upgrade

The Fusaka upgrade comprehensively covers these five phases at the architectural level and is hailed as a “scalability breakthrough upgrade.” This upgrade is scheduled to launch on December 3, 2025, and is the most far-reaching upgrade since the merge.

If the merger redefined Ethereum's consensus mechanism, then the Shapella upgrade reshaped its data processing model. This transformation is achieved through four core pillars:

• Node Data Availability Sampling (PeerDAS)
• blob capacity expansion in phases
• Gas limit increase
• Transition to Verkle trees for state representation and optimize block proposer selection mechanism

1. Node data availability sampling:

In the Dencun upgrade model, Rollup submits data in the form of blobs to Ethereum, and full nodes need to download and store these data blocks within the data availability window.

As the usage of Rollups increases, the amount of data per block may surge dramatically, leading to a spike in bandwidth requirements for validators. If left unaddressed, this trend could either result in centralization of validation (only resource-rich operators can keep up) or limit the capacity ceiling of Rollups.

Solution:

PeerDAS addresses this issue by redefining “data availability verification.” It no longer requires each full node to download all data blocks completely; instead, validators collaborate with other nodes to randomly sample data segments. If enough independent samples are successful, the probability of data loss or anomalies will be reduced to a very low level.

Core Impact:

• Bandwidth consumption reduced by 70%-80%
• Node operating costs reduced
• Improvement in decentralization level
• Rollup enables secure scaling

2. blob capacity expansion:

When the Fusaka upgrade is launched, the limit for blobs will maintain the standards of the Dengkun upgrade (the target value and maximum value per block remain unchanged), but the roadmap plans for subsequent “BPO” hard forks to gradually increase the limit to 10 blobs per block, ultimately reaching 14 data blocks.

Under the premise of alleviating bandwidth pressure with PeerDAS, Ethereum can withstand this expansion without pushing small node operators out of the network.

Blob Expansion Roadmap:

• Number of data blocks per block: 6 → 10 → 14
• Data volume increased by over 67%
• Rollup congestion issue alleviation
• Transaction fees further decrease

An exciting economic cycle is formed as a result:

• More data blocks → More Rollup → More transactions
• More transactions → More fee burning → Less supply

In short, Ethereum will further deflate while achieving scalability.

3. Gas limit increase:

In addition to the data layer transformation, the Fusaka upgrade will increase the block Gas limit from 45 million to 60 million. This does not mean that Ethereum will become a high-frequency execution engine, but it will indeed increase the execution capacity by about one third. Complex Decentralized Finance transactions, NFT minting, and other high Gas-consuming operations will have more room, reducing transaction failures caused by block saturation.

What needs to be weighed is that a higher Gas limit will accelerate state growth, increase the computational load of each block, and may put pressure on nodes with weaker performance. However, this cost will be alleviated by the supporting application of Verkle trees — Verkle trees can significantly compress state proofs and support a new lightweight verification model.

4. Verkle tree and state efficiency:

Currently, Ethereum uses Merkle Patricia trees to represent the global state (i.e., the mapping between addresses, storage slots, and their corresponding values). Although the concept of Merkle trees is simple, the generated proof files are relatively large, typically around 1 megabyte (MB). This results in high costs for light clients to verify the state of specific accounts and poses challenges for implementing stateless or semi-stateless nodes.

Verkle trees compress a large number of key-value pairs into a concise commitment through vector commitments. The proof document size corresponding to a single key will shrink by an order of magnitude, reducing from megabytes to tens of kilobytes (KB). This allows clients to verify the state with extremely low bandwidth and storage costs.

Core Achievements:

• The size of the proof documents is reduced by 90%
• Lightweight clients become a reality
• Mobile verification is feasible
• Stateless nodes gradually implemented

Deterministic Proposer Outlook

The Fusaka upgrade also enhances the predictability of block proposer selection. It allows participants to know in advance which validator will propose a specific block, creating possibilities for “forward-looking pre-confirmation” and more advanced transaction ordering and MEV mitigation schemes. Rollups that rely on Ethereum block ordering (such as projects using the “forward-looking ordering” scheme) can collaborate more efficiently with L1 validators. At the same time, a more transparent proposer scheduling mechanism helps reduce the incentives for manipulative behavior related to transaction ordering.

Summary

Looking at the upgrade history of Ethereum and Vitalik Buterin's roadmap, the Fusaka upgrade is not a one-time optimization, but rather the final realization of design decisions made years ago.

• PeerDAS and blob expansion push the “scaling” phase forward, enhancing the data throughput of Rollup;
• More predictable proposer selection and Rollup supporting infrastructure, aiding the “anti-MEV” phase, becoming an important component of the MEV governance toolkit;
• Verkle tree is the core of the “stateless” phase, providing support for stateless nodes and light clients;
• The increase in gas limits, optimization of state efficiency, and subsequent historical data cleanup are closely related to the “Purge” phase;
• The account abstraction and user-oriented optimizations initiated by the Pectra upgrade continue into the “Splurge” phase, and these optimizations rely on the capacity expansion and state efficiency improvements unlocked by the Deep Slope upgrade.

Strategic Significance

• Technical aspect: The Fusaka upgrade allows Ethereum to support transaction volumes far exceeding the current Rollup capacity, without sacrificing decentralization;
• Economic aspect: By allowing the growth rate of trading volume to far exceed the growth of supply, it deepened the correlation between network usage and ETH value;
• Governance and ecological aspects: Continuing the development model of Ethereum - upgrades driven by research and cautiously advanced, sacrificing short-term convenience for long-term robustness;
• Competitive Aspect: The Ethereum of the Fusaka era will be positioned as the “settlement and data availability layer,” supporting numerous high-throughput Rollups, rather than being an all-in-one monolithic chain.

High-speed, low-fee Layer 1 networks that compete directly on underlying throughput may still have specific niche markets, but Ethereum's bet is that a highly decentralized, economically sound, institutionally recognized settlement layer, layered with thousands of Rollup ecosystems, will form a more enduring architecture.

The Fusaka upgrade is by no means just another hard fork in a long list of upgrades. It marks the culmination of a decade of research and incremental upgrades in Ethereum, ultimately consolidating into a coherent, high-capacity, institutional-grade layer settlement platform—sufficient to support global financial and computing systems for decades to come.