Ethereum co-founder Vitalik Buterin has detailed plans for a sweeping, multi-year transformation of the blockchain and smart contract focused protocol that he describes as the network’s third major evolutionary phase. In a July 4, 2026 post on X, Buterin characterized the effort—internally referred to as “Lean Ethereum”—as comparable in scope and significance to the 2022 Merge, which transitioned Ethereum from proof-of-work to proof-of-stake.
Unlike that single, high-profile ETH blockchain upgrade, however, the new initiative will roll out gradually through a series of coordinated improvements spanning roughly three to four years.
The announcement follows recent in-person gatherings of Ethereum researchers in Berlin, building on earlier discussions held in Svalbard earlier in the year.
Two weeks ago, Ethereum researchers met in Berlin to continue charting the protocol's long-term trajectory, following along discussions with client teams in Svalbard in April.
The updated strawmap is at https://t.co/HZEerH1xxI, and I attached a picture of it to this post.
My… pic.twitter.com/KPGayHSySf
— vitalik.eth (@VitalikButerin) July 4, 2026
Buterin shared an updated high-level roadmap (a “strawmap”) and outlined how the changes will touch nearly every core layer of the protocol while prioritizing simplification, long-term security, and minimal disruption for existing applications and users.
Central to the vision is a shift in how the network verifies transactions.
Rather than relying primarily on direct re-execution by every node, verification will increasingly leverage recursive STARK proofs as a first-class, enshrined component of the protocol.
This architectural change is expected to improve efficiency and scalability. At the same time, the entire cryptographic stack will be upgraded to quantum-resistant alternatives to future-proof the system against potential advances in quantum computing.
Consensus-layer improvements are also planned.
The design envisions a decoupled structure separating data availability from finality, with one- or two-round finality mechanisms that aim to deliver both stronger theoretical security properties and faster confirmation times than today’s setup.
Additional technical upgrades include multidimensional gas pricing, evolution of the state model beyond traditional tree structures to accommodate new state types, and refinements to client architecture.
Privacy is being elevated from an optional feature to a core design requirement.
When planning updates to components such as the mempool, state tree, and related infrastructure, developers are explicitly considering how quantum-safe, intermediary-free private transactions will operate with acceptable overhead.
Formal verification of protocol components is another emphasized priority to enhance overall security and reduce implementation risks.
One of the most consequential areas of change involves Ethereum’s handling of state data. Current “dynamic” state will largely remain in place and receive only moderate scaling.
Alongside it, new categories of state optimized for scalability—though more restrictive in how they can be used—will be introduced.
These new state designs are expected to work particularly well for common use cases such as ERC-20 tokens, NFTs, and many decentralized finance applications.
Buterin noted that while no existing applications will be forced to rewrite their code, developers who migrate to the new state formats could see transaction fees drop by more than an order of magnitude.
As a rough illustration of the end state, Buterin suggested that by around 2030 Ethereum might maintain roughly 2 terabytes of traditional dynamic state while supporting up to 100 terabytes of the newer, more efficient state types.
Research is underway on incentive mechanisms to ensure nodes are properly motivated to store and serve this expanded dataset.The timeline includes a series of hard forks.
The upcoming H-star fork (also referred to as Hegota) is viewed as the last major upgrade with a predominantly pre-Lean character.
Subsequent forks, beginning with I-star, are expected to carry a strong Lean emphasis.
Incremental improvements to gas limits, blob data availability, and slot times will continue over the next five years, with a substantial gas-limit increase planned for the Glasterdam hard fork.
Throughout the process, the guiding principles remain simplification, cleanup of legacy elements, and future-proofing—approaches that proved successful during the Merge.
Buterin expressed confidence that the Ethereum ecosystem can execute another major reinvention while keeping the experience seamless for builders and users.
The “Lean Ethereum” effort signals a continued commitment to evolving the protocol in response to scaling demands, emerging security threats, and the desire for greater efficiency and privacy. As development progresses, further details and community feedback on new state designs and other components are expected.