At 14:50 UTC on October 21, Solana will activate the largest consensus-layer upgrade in its history:
Alpenglow.
It replaces TowerBFT, which has been running since Solana mainnet launched in March 2020.
Finality time: 12.8 seconds → 100–150 milliseconds.
Solana has always been called “fast”—but that refers to fast block production (one slot every 400 milliseconds), not fast finality. TowerBFT currently requires 32 slots of successive voting to reach irreversible finality, taking about 12.8 seconds in total. During that time, transactions can technically still be rolled back.
Alpenglow replaces TowerBFT with Votor, moving validator voting off-chain—instead of broadcasting vote transactions on-chain every slot, votes are aggregated off-chain, and only a proof of about 1,000 bytes is written on-chain.
The result: vote data that used to take about 500KB per slot is now compressed to 1,000 bytes, a 99.8% reduction.
The more immediate impact:
Currently, about 75% of all transactions on Solana are validator vote transactions. After Alpenglow is activated, those 75% will disappear, leaving all block space for actual user transactions.
Validator economics will also change: instead of paying about 1 SOL in vote fees per day, validators will pay an entry fee of about 1.6 SOL per epoch (VAT, burned directly)—which should help curb SOL inflation. The minimum profitable staking threshold will fall from about 4,850 SOL to about 450 SOL, opening up more room for smaller validators to survive.
The trade-off to note:
Byzantine fault tolerance drops from 33% to 20%—in other words, the tolerance for malicious nodes becomes more restrictive. In exchange, the “20+20” model (20% malicious + 20% offline, with the chain still remaining live) and deterministic, single-step finality.
This upgrade only includes Votor. Rotor, the block propagation layer, is a separate proposal for a later upgrade and has no timeline yet.
SOL is currently around $105–108. Will this upgrade drive the price up, or will it be a “sell the news” event? We’ll find out on October 21.
$SOL
#solanaalpenglow升级将于10月21日激活
Alpenglow.
It replaces TowerBFT, which has been running since Solana mainnet launched in March 2020.
Finality time: 12.8 seconds → 100–150 milliseconds.
Solana has always been called “fast”—but that refers to fast block production (one slot every 400 milliseconds), not fast finality. TowerBFT currently requires 32 slots of successive voting to reach irreversible finality, taking about 12.8 seconds in total. During that time, transactions can technically still be rolled back.
Alpenglow replaces TowerBFT with Votor, moving validator voting off-chain—instead of broadcasting vote transactions on-chain every slot, votes are aggregated off-chain, and only a proof of about 1,000 bytes is written on-chain.
The result: vote data that used to take about 500KB per slot is now compressed to 1,000 bytes, a 99.8% reduction.
The more immediate impact:
Currently, about 75% of all transactions on Solana are validator vote transactions. After Alpenglow is activated, those 75% will disappear, leaving all block space for actual user transactions.
Validator economics will also change: instead of paying about 1 SOL in vote fees per day, validators will pay an entry fee of about 1.6 SOL per epoch (VAT, burned directly)—which should help curb SOL inflation. The minimum profitable staking threshold will fall from about 4,850 SOL to about 450 SOL, opening up more room for smaller validators to survive.
The trade-off to note:
Byzantine fault tolerance drops from 33% to 20%—in other words, the tolerance for malicious nodes becomes more restrictive. In exchange, the “20+20” model (20% malicious + 20% offline, with the chain still remaining live) and deterministic, single-step finality.
This upgrade only includes Votor. Rotor, the block propagation layer, is a separate proposal for a later upgrade and has no timeline yet.
SOL is currently around $105–108. Will this upgrade drive the price up, or will it be a “sell the news” event? We’ll find out on October 21.
$SOL
#solanaalpenglow升级将于10月21日激活