Solana’s 150-millisecond settlement upgrade reaches second public test network
Alpenglow is running on both public test networks, giving application teams a place to check their software before the live blockchain switches.

Solana’s planned upgrade to make payments final in a fraction of a second has reached its public developer network, giving application teams a place to test before it reaches the blockchain carrying real money.
Called Alpenglow, the upgrade targets roughly 150 milliseconds for finality, the point at which a transaction can no longer be reversed, compared with about 12.8 seconds under the existing system.
That could shorten the wait for an exchange to release deposited funds or a payment app to tell a merchant a sale is complete.
Alpenglow changes how validators, the computers that check transactions, agree on the network’s records. They will exchange votes directly instead of recording those votes as transactions inside blocks, the batches of transactions added to the blockchain. Agreement can then take one or two voting rounds.