Solana tests Alpenglow upgrade to cut finality to 150 ms

Solana has moved its Alpenglow upgrade to the public test network, where validators will experiment with reducing transaction finality from roughly 13 seconds to 0.15 seconds.

What is being changed?

The upgrade replaces Solana’s current TowerBFT consensus mechanism with a new voting protocol called Votor. Votor allows validators to finalize blocks after one or two rounds of direct voting, eliminating the longer chain of on‑chain votes required by TowerBFT.

Impact on users and applications

Applications continue to execute transactions as before, and users do not need to modify wallets or change how they send funds. Faster finality means exchanges can credit deposits, bridges can release funds, and merchants can consider payments irreversible almost instantly.

Testnet rollout details

• The migration is being tested on Solana’s public testnet, which uses non‑monetary tokens.
• Validators must run Agave 4.3, the primary node software maintained by Anza.
• The testnet does not include alternative clients such as Firedancer or Frankendancer.
• Solana’s mainnet upgrade is tentatively scheduled for September 28, but this date is not confirmed for Alpenglow.

Background on the upgrade

Alpenglow has been running for over four months on a smaller, dedicated network. Moving it to the broader testnet checks whether the existing validator set can adopt the new protocol without disrupting the network.