Solana's devnet has migrated to Alpenglow, a new consensus protocol developed by engineers at Anza, marking a further step towards a network-wide overhaul of how the blockchain confirms transactions. The move, announced by Anza on 25 September, came a day after the testnet completed the same transition and followed a 17-minute countdown before the switch took effect at epoch 1167.
Alpenglow is designed to cut transaction finality from roughly 12.8 seconds under the current system to somewhere between 100 and 150 milliseconds. That reduction depends on validator response: when validators representing at least 80% of stake respond, finality arrives in about 100 milliseconds; in a fallback mode, it takes closer to 150 milliseconds. The protocol also introduces what its designers call a "20+20" fault tolerance model, meaning the network should remain stable even if 20% of validators go offline and a further 20% are compromised.
A new voting system
At the centre of the change is Votor, a voting system that replaces the TowerBFT algorithm Solana has used since launch. Votor was developed with input from researchers at ETH Zurich and was approved by validators through proposal SIMD-0326. Under the new design, validator coordination shifts largely off-chain, allowing the network to reach agreement in one or two voting rounds rather than the multi-step process TowerBFT required.
One practical consequence is that votes will no longer be recorded inside blocks themselves. The Solana Foundation has flagged that this will lower some activity charts and transaction totals, and it has asked data providers to adjust historical comparisons accordingly so that pre- and post-Alpenglow figures are not read as a genuine drop in network usage.
What developers need to do
According to a guide published by the Solana Foundation, applications that simply send transactions and read account balances will require no changes to work under Alpenglow. Services that build transaction histories, however, will need to keep competing candidate blocks separate until the network settles on one, since the finality process now resolves differently than under the old model.
No official date has been set for bringing Alpenglow to mainnet-beta, and the devnet and testnet migrations are being treated as staging steps rather than a finished rollout. Solana co-founder Anatoly Yakovenko offered a terse assessment of what the change represents, telling observers: "You're not ready for this."
