The Solana network is preparing for the Alpenglow consensus upgrade, scheduled for activation on October 21, 2026, at approximately 13:20 UTC. A readiness snapshot taken on October 20 identified 151 validators, representing 20.3% of the network's total stake, that have not yet met the new requirements.
To comply with the update, validators must run the Agave-based client version 4.3.2, register a BLS public key for off-chain signature aggregation, and maintain a minimum balance of 0.8 SOL in their vote accounts to cover the new Validator Admission Ticket fees.
The Alpenglow upgrade introduces the Votor component, which aims to reduce transaction finality from 12.8 seconds to approximately 150 milliseconds. The update also replaces the TowerBFT voting mechanism with an architecture based on aggregated BLS signatures and limits the active validator set to 2,000 participants.
The proposal for this overhaul received 98.27% approval in September 2025. While 20.3% of the stake remains unprepared, this represents an improvement from earlier figures, when approximately 45% of the stake, or 198 million SOL, did not meet the criteria. Validators failing to update may lose the ability to participate in voting.
