Solana (SOL) will switch to a new consensus system called Alpenglow on Oct. 21, aiming to make transactions final in about 150 milliseconds instead of roughly 12.8 seconds.
Key Points:
- Alpenglow is set to activate in epoch 1064, which should begin around 15:00 UTC on Oct. 21.
- Validators will stop posting votes on-chain, so reported transaction counts may drop sharply.
- The 150-millisecond finality goal is a target, and real-world results remain unproven.
Solana Alpenglow Schedule
The Solana Foundation published an updated timetable that places the switch in epoch 1064, expected to begin around 15:00 UTC on Oct. 21. Alpenglow will replace TowerBFT, the voting system the network has used since its 2020 launch. Epoch start times drift, so validators should track the epoch, not the clock.
Developer Anza, which builds the Agave validator client, said on Oct. 13 that the change caps "18 months of work for a migration that happens in one slot." The old system keeps running for the first 5,000 slots, about 18 minutes.
Today, validators record their votes as transactions on the blockchain. Under Alpenglow, they will swap votes directly and bundle enough approvals into a certificate that finalizes a block after one or two voting rounds.
Operators must run software built on Agave 4.3.0 and keep 0.8 SOL ready for a new per-epoch admission fee, while Firedancer and Frankendancer users must switch clients temporarily.
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Why Solana Finality Matters
Finality is the point where a payment can no longer be undone.
A Solana payment can already look complete almost instantly, but a merchant or a cross-chain bridge waiting for a firmer guarantee could act sooner. Still, the foundation cautioned that "the 150ms is an expectation, not a constant." Votes recently made up about 63% of all counted transactions, and the foundation called their coming removal from blocks an accounting change rather than lost throughput.
SOL Price Pressure
SOL has fallen about 9.3% over the past week to roughly $107, below its 20-day simple moving average, as U.S. spot Solana ETFs logged seven straight days of outflows. Analyst Crypto Patel flagged $96 to $103 on the eight-hour chart as a possible buying zone, with $125 and $150 as upside targets if a reversal is confirmed.
Anza unveiled Alpenglow in May 2025, and validators approved it that September with about 98% support. Developers once hoped for a first-quarter mainnet launch. Instead, the upgrade reached Solana's testnet on Sept. 24 and its devnet a day later, after five months of rehearsals on a community cluster.
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