Solana Schedules Alpenglow Mainnet Upgrade for Oct. 21, 2026

Solana is scheduled to begin activating Alpenglow on its mainnet Oct. 21, 2026, in a change to validator consensus designed to cut transaction finality from about 12.8 seconds to a target of roughly 150 milliseconds. The activation is expected to start with epoch 1064 at about 11 a.m. ET (15:00 UTC). The time is an estimate because epoch timing can shift. TowerBFT is scheduled to continue for 5,000 slots, or about 18 minutes, after the feature gate turns on, with Alpenglow expected to take over at slot 459,653,000.