Solana sets Oct. 21 for Alpenglow upgrade targeting 150-millisecond finality

Solana has scheduled Oct. 21 for Alpenglow, a major upgrade aimed at making transactions irreversible in roughly 150 milliseconds by changing how the computers running the network agree on payments.

The updated timetable published by the Solana Foundation sets a date for replacing TowerBFT, the voting system Solana has used since its launch in 2020. The 150-millisecond figure remains a target, with actual performance depending on network conditions.

A Solana payment can already appear successful almost immediately. But Alpenglow aims to give it the stronger guarantee that it cannot be undone almost as quickly.

A merchant waiting for that assurance before accepting a payment, or a bridge before releasing funds on another blockchain, could act sooner.

As of today, validators, or the computers that check transactions and help secure Solana, submit their votes as transactions recorded on the blockchain. Alpenglow will allow them to exchange votes directly and combine enough approvals into a type of certificate that makes a block final after one or two voting rounds.