Ethereum co-founder Vitalik Buterin published his takeaways from an updated version of the network's draft long-term roadmap, describing the multi-year "Lean Ethereum" effort as a near-total rebuild of how the network operates.
In an X post Saturday, Buterin wrote that Lean Ethereum "is not a single one-shot upgrade" but a series of improvements arriving over three or four years. Still, he called it "the third major iteration" of Ethereum, on par with the Merge, adding that "almost every major piece of the protocol will be replaced."
The post follows a meeting of Ethereum researchers in Berlin in late June, Buterin said. The revised plan is published at strawmap.org, the draft roadmap that Ethereum Foundation researcher Justin Drake introduced in February, which outlines seven network upgrades through 2029.
The changes Buterin listed touch nearly everything: how the network confirms transactions are valid, the cryptography protecting it from future quantum computers, how quickly transactions become final, and how the chain stores its data. He said the transition can happen without breaking existing apps, writing, "We've done this before (the Merge), we can do it again."
Buterin also gave the effort a timeline marker, saying Hegota, currently slated as Ethereum's second upgrade of 2026, is probably the network's last thematically "pre-Lean" fork. In other words, nearly every upgrade after this year will be part of the rebuild.
