Solana Activates Alpenglow Consensus Overhaul on Testnets

Solana has activated its Alpenglow consensus overhaul on two public test networks, replacing TowerBFT with Votor. This change aims to reduce transaction finality time from approximately 12.8 seconds to just 100-150 milliseconds.

On September 24, Anza activated Alpenglow on the testnet cluster, followed by devnet on September 25. The transition was marked by a 17-minute countdown, during which validators switched from TowerBFT to Votor.

The Alpenglow system uses offchain voting, collecting peer-to-peer votes into compact BLS certificates, and operates two confirmation paths simultaneously: fast path with 80% of stake agreeing in one round (targeting 100 milliseconds), and fallback with 60% agreeing initially followed by another round (targeting 150 milliseconds).

While the testnet cluster achieved over 25,000 transactions per second with 150-millisecond finality, mainnet conditions remain unproven. The Solana protocol still needs to complete its transition, and Anza is warning infrastructure providers to prepare for changes in reported transaction counts.