Solana Alpenglow Upgrade Set for October 21, Cutting Finality to 150 Milliseconds

Solana’s Alpenglow consensus upgrade is scheduled to go live on mainnet on Wednesday, October 21, 2026, cutting transaction finality from roughly 12.8 seconds to about 150 milliseconds, according to the Solana Foundation’s upgrade page . The change replaces the network’s TowerBFT voting mechanism with a new protocol called Votor and is the first major replacement of Solana’s consensus layer since TowerBFT. SOL was trading near $104 on October 14, down roughly 3.7% over the prior 24 hours, as validators and infrastructure providers prepared for the migration.