Solana core developers have pushed a sweeping consensus overhaul, “Alpenglow” (SIMD-0326), into the ecosystem’s formal governance track, setting up a validator vote that, if approved, would replace TowerBFT and re-architect finality and validator incentives on mainnet-beta. The proposal’s authors—Quentin Kniep, Kobi Sliwinski, and Roger Wattenhofer—describe Alpenglow as “a major overhaul of Solana’s core consensus protocol,” designed to supplant “the existing Proof-of-History and TowerBFT mechanisms” with a design that targets block finalization “as low as 100–150 milliseconds.”
The upgrade also rewires validator economics. Because voting moves off-chain, the SIMD introduces a Validator Admission Ticket (VAT), a fixed per-epoch fee “initially set to 1.6 SOL per epoch,” burned to maintain an economic barrier roughly comparable to today’s on-chain vote-fee regime. Validators are “required to cast exactly one valid vote per slot”; conflicting votes are detectable, and persistent non-participation renders a validator ineligible for rewards and at risk of removal from the active set.
Leaders receive compensation equal to the per-slot vote rewards of the votes they aggregate, plus a flat bonus when they include fast-finalization/finalization certificates. In a follow-up thread post, Wattenhofer explains the 1.6 SOL figure as approximately 80% of current vote costs to ensure no operator is worse off at the “AlpenSwitch.”
If adopted, Alpenglow would make a visible semantic change at the client layer: the authors note that optimistic confirmation would be superseded by actual finality at sub-second timescales. The stated aim is to bring confirmation latencies in line with Web2 user expectations while tightening safety guarantees that were harder to formalize under TowerBFT. The proposal’s documentation points readers to a 50+ page white paper and independent analyses, but emphasizes that the initial rollout focuses on finalization and voting; a new data dissemination protocol, Rotor, would follow in a separate SIMD.
Governance mechanics for the vote mirror Solana’s prior advisory processes but with higher stakes. Vote tokens will be claimable via an adapted Merkle distributor; validators then send those tokens to the designated choice accounts during the epoch-bounded window. The foundation’s governance post states, “If the sum of Yes votes is equal to or greater than 2/3 of the total sum of Yes + No votes, the proposal will pass,” and “Abstain” contributes to quorum but not to the supermajority tally. Stake weights and a public tally script will be published for independent verification.
At press time, SOL traded at $181.89.
