Vitalik: Ethereum to enter 'Lean Ethereum' phase, core protocol may undergo full overhaul in the next 3–4 years

Ethereum co-founder Vitalik Buterin published a post stating that Ethereum researchers recently held a meeting in Berlin, continuing discussions with client teams initiated in Svalbard in April, to update the blockchain’s long-term protocol roadmap. Vitalik noted that "Lean Ethereum" is not a single upgrade, but a series of protocol evolutions to be rolled out gradually over the next 3 to 4 years—its impact is comparable to The Merge as Ethereum’s second major iteration, while the current phase may mark its third major evolution. He outlined core upcoming changes for Ethereum: replacing direct execution verification with recursive STARK proofs, integrating post-quantum cryptography, adjusting the consensus mechanism to a decoupled design of available chain and finality, and implementing multi-dimensional gas models alongside state structure restructuring. At the state level, Ethereum may form a "two-tier state structure" around 2030, consisting of ~2TB of traditional dynamic state and ~100TB of new scalable state to support scaling needs across different application scenarios. Vitalik emphasized that privacy capabilities will no longer be an add-on feature, but a core goal of protocol design. The system will also rely more on formal verification to boost security, and push the EVM toward higher-level abstractions, with the underlying layer potentially transitioning gradually to RISC-V or leanISA architectures. Key parameters including gas limits, blob sizes, and block times will be adjusted multiple times over the next few years, as Ethereum continues scaling via client optimizations and protocol upgrades. Vitalik concluded that Ethereum is entering a phase of continuous restructuring and scaling, aiming to complete underlying system upgrades without disrupting the existing application ecosystem.