Solana activated Alpenglow on Oct. 21, replacing TowerBFT with a consensus system targeting 150-millisecond finality that Anza says could speed payment processing and exchange deposits.
The Solana Foundation lists TowerBFT finality at about 12.8 seconds and calls 150 milliseconds Alpenglow’s target. Anza says transactions now become final in about that time.
Alpenglow changes how validators establish agreement. Instead of putting individual votes in on-chain transactions, validators exchange vote messages and assemble approvals into certificates. The SIMD-0326 proposal sets two paths to finality: one voting round with support from 80% of stake, or two rounds with 60% thresholds.
The upgrade also changes what voting validators pay. The Foundation says they now pay a flat 0.8 Solana (SOL) per epoch through a ticket debited from their vote accounts and burned. Under TowerBFT, vote transaction fees cost about 1 SOL per epoch.
The handoff took place at slot 459,653,000 after TowerBFT continued for 5,000 slots, or about 18 minutes, following the start of epoch 1064. The Foundation says the switch itself took about 900 milliseconds. It records that 446 of Solana’s 654 validators voted to certify Alpenglow’s genesis block. The transition follows earlier coverage of Solana’s validator-vote changes.
Anza expects shorter confirmation times to help services that depend on quick settlement, such as point-of-sale payments and exchange deposits.
Further work named by Anza includes Rotor, geographically aware leader rotations and Quantumglow, with no committed dates. The Foundation describes Rotor as a planned change to block propagation but has not scheduled its release.
