Solana is testing Alpenglow on its public testnet, an upgrade designed to reduce transaction finality from around 13 seconds to as little as 150 milliseconds.
The faster finality could allow exchanges, bridges and merchants to treat transactions as irreversible almost immediately after they are processed.
Finality is the stage at which a blockchain transaction is considered permanent. Crypto exchanges typically wait for it before crediting deposits, bridges use it before releasing funds on another network, and merchants depend on it to confirm that payments cannot be reversed.
Alpenglow is being introduced on Solana’s public test network, which replicates the blockchain but uses tokens with no monetary value. Developers can therefore test the upgrade, identify bugs and restart the network without exposing actual user funds.
Solana currently uses TowerBFT for consensus, allowing validators to agree on which transactions should become part of the permanent ledger. Validators record votes on the blockchain and accumulate enough support over 32 slots before a block reaches finality.
Alpenglow would replace TowerBFT with Votor, a new voting protocol that allows validators to communicate directly. A block could reach finality after one or two rounds of voting, removing the longer sequence of onchain votes used under the existing system.
The upgrade is not expected to change how users interact with Solana. Applications can continue processing transactions normally, and users would not need to switch wallets or adopt a new process for sending funds.
Alpenglow has already spent more than four months running on a dedicated smaller network built to test the upgrade. Bringing it to Solana’s established testnet will test whether the wider collection of hardware and services supporting the blockchain can migrate successfully.
The test requires participating validators to run Agave 4.3, Solana’s primary validator software. Anza, one of the companies developing the network, maintains Agave.
Anza recommended Agave 4.3 to mainnet validators on Sept. 21 after initially deploying it to operators representing 10% and later 25% of the SOL securing the network.
Jump Crypto’s alternative validator clients, Firedancer and Frankendancer, do not currently support the Alpenglow test.
The alternative clients are intended to diversify Solana’s validator software and reduce dependence on Agave, so a problem affecting one implementation does not necessarily impact the entire network. Since they are not yet part of the test, the initial Alpenglow migration will rely entirely on Agave.
Anza’s current schedule lists Sept. 28 as a tentative date to activate features included in Agave 4.3 on mainnet. That date does not represent a confirmed Alpenglow launch, and the company’s tracker still showed the testnet activation as pending early Wednesday.
