Solana schedules Alpenglow upgrade for October 21

The Solana Foundation set October 21 as the planned activation date for Alpenglow, a replacement for the network's TowerBFT voting system. Alpenglow aims to bring finality, the point after which a confirmed transaction should not be reversed, closer to 150 milliseconds under suitable network conditions.

Validators will exchange and aggregate votes offchain rather than recording every vote as a normal transaction. That creates a reporting wrinkle: total onchain transaction counts could fall substantially after activation even if genuine user activity stays unchanged.

Operators must prepare for a software migration, including a temporary switch away from alternative validator implementations that do not yet support the initial transition. The advertised finality remains a target until mainnet performance can be observed.