Solana Activates Alpenglow Upgrade, Targeting 150-Millisecond Finality

Solana activated its Alpenglow consensus upgrade Wednesday, targeting transaction finality of about 150 milliseconds and a shorter wait for exchanges and payment apps that must confirm transfers.

The change took effect during epoch 1064 at slot 459,653,000. Finality is the point after which a transaction cannot be reversed. The 150-millisecond figure is the upgrade’s target.

Alpenglow changes how validators agree on transactions. They send votes off-chain and combine them into certificates instead of recording each vote as a transaction. The design allows a transaction to become final after one or two voting rounds.

The upgrade also changes validator costs. A fixed admission fee of 0.8 Solana (SOL) per epoch, a period of about 24 hours, replaces voting fees. That removes the need for validators to pay for each vote they submit.

Before the mainnet switch, the test network was cleared and restarted six times after testing began in early May. One attempt to migrate the entire test network failed and was rolled back; a later attempt succeeded. Alpenglow is Solana’s largest network upgrade since its 2020 launch.