Solana has advanced its Alpenglow upgrade to its public test network as developers begin testing a significant reduction in transaction finality times. The upgrade aims to cut the time required for payments to become irreversible from about 12.8 seconds to 0.15 seconds.
Transaction finality is a critical measure for blockchain functionality. Exchanges require finality before crediting deposits, bridges need it before releasing funds on other blockchains, and merchants depend on it to verify that payments cannot be reversed.
Alpenglow replaces Solana's existing TowerBFT consensus system with a new voting protocol called Votor. Under the current system, validators record votes on the blockchain and accumulate them across 32 slots before a block becomes final. Votor enables validators to send votes directly to one another and finalize blocks after just one or two rounds of voting.
The upgrade has already undergone more than four months of testing on a specialized network. Moving it to Solana's established testnet allows the broader network of computers and services running the blockchain to test switching together. Users will not need to change wallets or modify how they send funds, as applications will continue operating as they do today.
Validators participating in the testnet migration need Agave 4.3, the primary software used to run Solana and maintained by Anza. Anza recommended Agave 4.3 to all mainnet validators on September 21 after initially rolling it out to operators responsible for 10% and then 25% of the SOL securing the network.
Anza's schedule lists September 28 as a tentative date for activating features included in Agave 4.3 on the main network. This date is not confirmed as the official Alpenglow launch date.
