Overview
- The Alpenglow upgrade, scheduled to activate on Oct. 21, 2026, will replace TowerBFT with a new Votor design that aims for roughly 150 millisecond finality for participating validators.
- Validators must run compatible clients such as Agave 4.3.2, Jito-Solana or Harmonic Salsa and keep at least 0.8 SOL in their vote accounts to pay the Validator Admission Ticket or be excluded from voting.
- RPC and node operators have warned the consensus handoff may cause a short pause in new transactions and one-time data-stream interruptions that could show slots that never reach confirmation.
- Alpenglow moves vote data off-chain into certificates, so indexers, explorers and dashboards must rebaseline counts and some unstaked or default RPC nodes may learn finality later than admitted validators.
- The upgrade cleared governance with strong support in September 2025 and was tested on devnet and testnet; the separate Rotor data-distribution work remains deferred and ordinary users do not need to change how they sign transactions.