Solana Alpenglow Upgrade Hits Public Testnet

Solana has begun moving its Alpenglow consensus upgrade onto the public testnet, marking a crucial step towards shrinking transaction finality to a fraction of its current time. The network's validator community will now be able to exercise this change, which targets a cut in finality from roughly 12.8 seconds to about 150 milliseconds.

The Alpenglow upgrade replaces TowerBFT with Votor, a protocol that allows validators to pass votes straight to one another and agree on a block within a round or two. This removes the drawn-out on-chain voting chain that makes up most of the delay, reducing the wait time for transactions.

Agave v4.3.0 has been published as a stable build suitable for testnet, devnet, and mainnet beta, and all mainnet validators have been instructed to run it after staged rollouts to operators controlling about 10% then 25% of staked SOL. The first Alpenglow migration will rely solely on Agave, with Firedancer and Frankendancer not yet supporting the testnet.

The tentative date for enabling the Agave 4.3 features on the main network is September 28, though Anza has not confirmed a launch.