Ethereum outlines the sequence toward Lean
The Foundation describes successive upgrades toward its 2029 goal, giving builders a planning framework rather than a deployment date.
The Ethereum Foundation has described a fork sequence for reaching its Lean Ethereum goal by 2029. Its November 4 post places leanVM and lean transactions in I*, followed by lean attestations, data availability sampling and PCS in J*. It presents L* as the point of completion, with H* preceding the Lean features.
That sequence matters because execution changes and consensus changes have different integration costs. Teams can use the proposed order to organize research, client compatibility work and testing, instead of treating Lean as a single switch.
The post describes a plan. It does not establish that these features are deployed or that every milestone has an activation date. For application and infrastructure teams, the useful next step is to follow concrete specifications and client releases as the sequence develops.