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Solana’s Alpenglow upgrade goes live, targeting 150ms finality

Solana activated Alpenglow on Oct. 21, replacing its 2020 consensus system and targeting 150ms finality, a change that could speed payments without wallet changes.

The Aeterna Sol Editors

Solana’s Alpenglow upgrade goes live, targeting 150ms finality

150 milliseconds is Solana’s target for transaction finality under Alpenglow, the new consensus protocol that went live on mainnet on Oct. 21. That is down from about 12.8 seconds under the previous system, which could mean you wait less time for a payment or trade to become irreversible.

The Solana Foundation says Alpenglow activated at the start of epoch 1064. The Foundation’s upgrade overview says everyday users do not need to change how they sign or send transactions, and wallets and apps continue to work as before.

What changed in Solana’s consensus system?

Alpenglow replaces TowerBFT, the consensus protocol Solana had used since its 2020 launch. Consensus is how validators agree on transaction order and when a transaction can no longer be reversed.

Under TowerBFT, validators recorded votes as onchain transactions, and enough votes had to accumulate before a block became final. Alpenglow’s Votor protocol moves those votes offchain: validators send votes directly to one another and combine them into certificates, allowing a block to become final after one or two voting rounds.

The handoff took place at slot 459,653,000, according to the Foundation. The change affects how the network agrees on blocks; it does not change transaction execution, fees or the Solana Virtual Machine.

How could faster finality affect you?

When finality arrives faster, an app or merchant can have less time to wait before treating a transaction as irreversible. That may make payments and trades feel more immediate, although the 150ms figure is a target and actual timing depends on network conditions.

For you as a wallet user, the Foundation says there is no migration step. You can keep using your existing wallet and apps. Developers who only send transactions and read account data also do not need to migrate, but infrastructure that streams or indexes blocks may need updates.

One visible change is that validator votes no longer appear as transactions in blocks. That will lower headline transaction counts and some TPS figures, but the count change alone does not mean user activity has fallen. Developers and data providers will need to account for the missing vote transactions when comparing network metrics.

What does the switch require from validators?

Validators had to prepare for the change before the mainnet handoff. The Foundation says operators must run version 4.3.2 of an Agave-based client, such as Agave, Jito-Solana or Harmonic Salsa, and keep at least 0.8 SOL above the rent-exempt minimum in the vote account for the Validator Admission Ticket fee.

The upgrade also affects data services that read Solana’s block streams. The Foundation says those services must handle changes including multiple candidate banks within a slot and the removal of vote transactions. If you simply send transactions through an app, those infrastructure details should not require action from you.

CoinDesk’s report on Alpenglow’s launch described the upgrade as Solana’s biggest network overhaul since 2020. The first phase, Votor, is now live; the Foundation says Rotor, a separate change to how block data spreads across the network, is planned for a later release and has no schedule yet.

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