Solana Sets a Date for Its Next Major Upgrade

In brief

• Alpenglow activates on Solana mainnet in epoch 1064, which starts on Wednesday, October 21, at approximately 15:00 UTC, according to the Solana Foundation.
• The upgrade replaces TowerBFT and targets transaction finality of roughly 150 milliseconds, down from about 12.8 seconds today.
• Vote transactions will leave blocks, so Solana's headline transaction counts and TPS figures will drop sharply without any drop in real activity.

Solana has locked in October 21 for Alpenglow, a full replacement of the system its validators use to reach consensus. The switch is tied to epoch 1064, which the Solana Foundation expects to begin around 15:00 UTC that Wednesday.

Alpenglow retires TowerBFT, the current system the network uses, and aims to make transactions final in roughly 150 milliseconds. Finality is the moment a transaction becomes irreversible, and under TowerBFT that currently takes about 12.8 seconds.

On Solana today, a payment is confirmed pretty quickly, but that’s not a guarantee. Until TowerBFT runs out its 13 second clock, the block could in theory still be dropped.

That small doubt is why anyone handling real money tends to wait out the full window. With finality at around 150ms, the irreversible answer arrives almost as fast as the optimistic one, which is what a checkout counter taking SOL or a DeFI application, or a trading desk settling a position actually needs.