Solana Alpenglow upgrade targets 150ms finality in October

Solana is preparing to replace TowerBFT with Alpenglow, a new consensus design that targets roughly 150 millisecond finality, down from about 12.8 seconds today. Summary Solana’s Alpenglow upgrade targets roughly 150 millisecond finality, down from about 12.8 seconds under TowerBFT. Solana Foundation now targets Alpenglow activation through Agave 4.3 in October, not a September date. Agave 4.2 already contains Alpenglow code, allowing testing before the consensus switch reaches mainnet deployment. Anza opened a security competition offering up to 50,000 SOL before Alpenglow’s planned mainnet activation. Validators approved SIMD-0326 with 98.27% support in September 2025, authorizing development of the consensus overhaul. The latest official roadmap, however, does not confirm a September activation. Solana Foundation says Alpenglow is expected to activate with Agave 4.3, which is targeted for October 2026. The distinction matters because an Aug. 14 discussion around Solana co-founder Anatoly Yakovenko’s comments revived claims that the upgrade could arrive as soon as September. Yakovenko said finality is “really only important at the cash register,” referring to situations where use...