Solana targets 150ms transaction finality with Oct. 21 upgrade

Solana will activate its Alpenglow upgrade on October 21, targeting transaction finality in under 150 milliseconds. The upgrade replaces TowerBFT with Votor, reducing validator voting delays and costs. Validators must migrate to Agave 4.3.0, while Firedancer and Frankendancer clients are excluded from the initial migration. October 21 is reserved for the launch of Alpenglow, a protocol upgrade that aims to guarantee an irrevocable transaction in less than 150 milliseconds and remove the TowerBFT voting system the platform has used since 2020. While a Solana transaction may already become successful instantaneously, the difference is in the guarantee that stands behind it.