Researchers working with the Ethereum Foundation, including Vitalik Buterin, have laid out a long-range plan to reach what they call Lean Ethereum by the end of 2029, according to research findings. The plan relies on a sequence of roughly seven hard forks and is designed to keep backward compatibility for existing applications, so apps already running on Ethereum should not need to be rebuilt from scratch.
A third major version
Lean Ethereum is framed as the third major version of the protocol. The first was the original launch, and the second arrived with the 2022 Merge, which replaced how the network reaches consensus. This third iteration goes broader, targeting upgrades to the network's three core layers: consensus, execution and data.
The fork sequence uses placeholder labels running from fork H* through fork L*, with the explicit ordering of those upgrades clarified on November 5, 2026. The final fork, L*, is the one that would complete the Lean Ethereum transition.
Named upgrades near the front
Two named upgrades sit near the front of the line. Glamsterdam is on deck, and Hegotá is expected to be the last fork before the full Lean Ethereum transition, slated for late 2026 or early 2027.
The technology under the hood
Two components stand out in the plan: quantum-safe, hash-based signatures and recursive STARK proofs for verifying transactions.
- Hash-based signatures rely on a different kind of math, one built to hold up even against quantum attackers.
- STARK proofs allow one party to prove a batch of computation was done correctly without everyone else redoing the work. Recursive STARKs take it further: proofs can verify other proofs, compressing huge amounts of activity into something small and quick to check.
The plan also introduces a two-tier state model. Tokens using that scalable tier are projected to see fee reductions of over 10x. That is a projection, not a guarantee, and it applies specifically to the new tier rather than to every transaction on the network.
How the plan took shape
The research findings trace the strategic roadmap back to February 2026, with significant updates in November 2026 focused on how the forks should be sequenced. The Lean Ethereum plan was first proposed by researcher Justin Drake in mid-2025 and solidified in a strawmap released in February 2026.
Buterin has pointed to the looming threat of quantum computing as a driving force behind the accelerated focus on post-quantum security, with quantum capabilities anticipated around 2030.
What it means for users
For users, the projected fee reduction on the scalable tier is the most tangible piece. A projected cut of more than 10x on that tier would be a meaningful change if it holds up in practice.
The research findings note that building in post-quantum readiness now could set Ethereum apart from blockchain platforms that have not yet addressed the issue. They also flag that community reception of the Glamsterdam and Hegotá forks will be a key early read on support and adoption.
