Solana has scheduled Oct. 21 for Alpenglow, a major upgrade designed to make transactions irreversible in roughly 150 milliseconds by changing how validators on the network confirm payments. The upgrade targets faster finality, though actual performance will depend on network conditions.
Alpenglow will replace TowerBFT, Solana's voting system since its 2020 launch. Currently, validators submit their votes as transactions recorded on the blockchain. Under Alpenglow, validators will exchange votes directly and combine approvals into certificates that make blocks final after one or two voting rounds.
The faster finality could benefit merchants and bridges waiting for payment assurance before acting. While Solana transactions already appear successful almost immediately, Alpenglow aims to provide stronger guarantees that transactions cannot be reversed nearly as quickly.
The upgrade will create a notable change in reported metrics on activation day. Solana's transaction count may fall sharply because validator votes will no longer appear as transactions in blocks, even if user activity remains unchanged.
Validator Preparation and Technical Details
Validators must prepare for the migration by upgrading to Agave 4.3.0. Operators of Firedancer and Frankendancer, alternative validator software, will need to switch temporarily, as these programs will not support the initial migration.
The migration is scheduled for epoch 1064, expected to begin around 15:00 UTC on Oct. 21. Solana will continue using its old voting system for the first 5,000 slots—roughly 18 minutes—before switching to Alpenglow.
Validator compensation will also change. Current voting charges of approximately 1 SOL per epoch will be replaced by a flat admission fee of 0.8 SOL per epoch.
