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Solana Sets Oct. 21 Alpenglow Upgrade With 150-Millisecond Finality Target
Validator voting moves off-chain as Solana prepares to reset transaction metrics
TL;DR
- Solana’s Alpenglow migration is scheduled to start Oct. 21, targeting transaction finality in roughly 150 milliseconds.
- Votor will replace TowerBFT and remove validator votes from blocks, potentially causing headline transaction counts and TPS to fall without weaker user activity.
- Validators face new software and fee requirements, while recent DefiLlama data shows Solana leading Ethereum and Base in DEX volume.
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Solana has scheduled its Alpenglow mainnet migration for Oct. 21, 2026, a major consensus overhaul targeting transaction finality in roughly 150 milliseconds. The upgrade will replace TowerBFT with Votor, move validator voting off-chain and change how Solana transaction activity should be measured after activation. The finality figure remains a target, with actual performance depending on network conditions.
Alpenglow Replaces TowerBFT With Direct Validator Voting
TowerBFT has been Solana’s voting system since the network launched in 2020. Validators currently submit consensus votes as normal on-chain transactions, with votes accumulating across 32 slots before a block reaches the strongest settlement guarantee, producing a wait of roughly 12.8 seconds. Votor instead lets validators send votes directly to each other and combine approvals into certificates that finalize blocks after one or two voting rounds.
The mainnet migration is scheduled for epoch 1064, expected to begin around 15:00 UTC. Solana will keep TowerBFT for the first 5,000 slots before switching about 18 minutes later at slot 459,653,000. The release covers Votor, while Rotor, an Alpenglow component intended to replace the Turbine block-propagation system, is planned for a later release.
The finality target does not mean Solana will produce a new block at the same interval. Slot times were separately reduced to 200 milliseconds in October. Faster finality could reduce consensus-related waits for services that hold deposits, goods or transfers until settlement is final, although delays imposed by exchanges, bridges, payment providers or other chains would remain.
Validators and Solana Data Providers Face New Requirements
Validator operators must migrate to software built on Agave 4.3.0. Firedancer and Frankendancer will not support the initial transition, requiring operators using those clients to switch temporarily. Current voting charges of roughly 1 SOL per epoch will disappear and be replaced by a flat 0.8 SOL Validator Admission Ticket fee; vote accounts must hold the required amount above the rent-exempt minimum.
Ordinary wallet and application users are not expected to change how they sign, send or approve transactions. Solana’s transaction format, programs, account model and user fees remain unchanged. Indexers, explorers and data providers, however, must account for the new bank_id field because a slot can contain more than one candidate block, while tools tracking validator participation must read certificates from Alpenglow’s block footer instead of Vote Program instructions.
The most visible data change could be a sharp decline in reported transactions and TPS once validator votes disappear from blocks. Solana guidance calls for throughput dashboards to re-baseline their data. Analysts can instead compare non-vote transactions, active fee payers, stablecoin transfer activity, DEX volume and unique traders, fee revenue and application-level usage before concluding that network demand changed.
Solana Leads Recent DEX Volume Before the Upgrade
Recent DefiLlama data showed Solana ahead of Ethereum and Base in decentralized exchange activity across several periods.
The change in voting means those application-level measures could become more useful when comparing Solana activity across the upgrade. A lower headline transaction count by itself would reflect the removal of validator votes from blocks and would not establish that users or applications had become less active.
This article has been refined and enhanced by ChatGPT.
