Solana Starts Testing Upgrade That Could Cut Finality From 13 Seconds to 0.15 Seconds

Solana Moves Alpenglow to Public Testnet

Solana has moved a planned upgrade called Alpenglow onto its public testnet, where developers will test whether the blockchain can confirm transactions almost instantly instead of waiting about 13 seconds.

The upgrade could reduce the time it takes for a payment to become irreversible from roughly 13 seconds to about 0.15 seconds. That moment is known as finality. Exchanges wait for finality before crediting deposits, bridges wait before releasing funds on another blockchain, and merchants need it to confirm a payment cannot be reversed.

Key Details of the Alpenglow Upgrade

• Alpenglow replaces Solana's current TowerBFT consensus system with a voting protocol called Votor.
• Under Votor, validators send votes directly to one another and can settle on a block after just one or two rounds, instead of recording votes across 32 slots.
• Users will not need to change their wallets or how they send funds during the upgrade.
• Alpenglow spent more than four months running on a smaller test network before moving to Solana's established public testnet.

How Votor Replaces TowerBFT

Solana currently uses TowerBFT to reach consensus, which is the process through which validators agree on which transactions belong in the permanent record. Validators stack enough recorded votes across 32 slots before a block becomes final.

Alpenglow replaces that with Votor. Validators communicate directly and can finalize a block after one or two rounds of voting, removing the longer chain of onchain votes. Applications continue executing transactions as they do today.

Testing Progress and Software Requirements

Validators taking part in the testnet need Agave 4.3, the main software used to run Solana, maintained by Anza. Anza recommended Agave 4.3 to all mainnet validators on Sept. 21 after first rolling it out to operators responsible for 10% and then 25% of the SOL used to secure the network.

The initial testnet migration runs entirely through Agave. Two alternatives, Firedancer and Frankendancer, which are intended to reduce reliance on a single piece of software, are not supported in this early phase.

What Remains Unclear

Sept. 28 appears in Anza's schedule as a tentative date for turning on features included in Agave 4.3 on the main network. However, this is not a confirmed Alpenglow launch date. As of the source's publication, Anza's tracker still listed the testnet switch itself as pending early Wednesday.

Why This Matters

Faster finality would benefit exchanges, bridges, and merchants by allowing them to treat payments as irreversible almost immediately. This could improve the speed and efficiency of transactions across the Solana ecosystem without requiring changes to how users interact with the network.

Sources

• CoinDesk