# Solana Activates Alpenglow on Testnet for Faster Transaction Finality

By Simon Yoon

Canonical URL: https://www.tokenpost.com/news/technology/24478
Published: 2026-09-26T21:48:26.000Z
Updated: 2026-09-26T21:48:26.000Z
Section: Technology

> The upgrade targets about 150-millisecond finality overall, with a fast path targeting 100 milliseconds, but neither has been demonstrated on mainnet.

Solana activated its Alpenglow consensus upgrade on public testnet Thursday, Sept. 24, and devnet Friday, Sept. 25, advancing a protocol change designed to reduce transaction finality from seconds to milliseconds.

The upgrade’s overall design target is about 150 milliseconds, compared with roughly 12.8 seconds under Solana’s existing TowerBFT consensus system. Its fast path targets about 100 milliseconds when validators representing 80% of stake notarize a block in one round.

Those figures remain protocol targets for test environments. The performance has not been demonstrated under full mainnet conditions.

Alpenglow’s first phase, Votor, replaces TowerBFT voting with direct validator votes and aggregate certificates. The upgrade also removes validator vote transactions from the normal transaction flow and uses aggregated BLS signatures.

The change is limited to Solana’s consensus layer. The Solana Virtual Machine, programs, transaction format and fees remain unchanged for users, and no wallet or transaction migration is required.

Validators, indexers and other infrastructure providers face the main integration work. Systems that process block and finality data may need to support multiple banks per slot and a new bank_id field.

Votor’s fast path requires 80% of stake to notarize a block in one round. If that path fails, a fallback process uses a 60% stake threshold across a second round. The protocol is designed to tolerate 20% malicious stake alongside 20% offline stake while still reaching consensus.

Rotor, a planned replacement for Solana’s Turbine block-propagation system, is scheduled for a later phase and is not part of the initial Votor transition.

The testnet milestone follows Solana’s earlier Alpenglow activation plan. The testnet cluster lists Alpenglow as its consensus system and records a genesis slot of 444,625,255.

No confirmed Alpenglow mainnet activation date has been provided. Mainnet consensus activation is tied separately to the Agave 4.3 implementation path.

## Links in this article

- [Solana’s earlier Alpenglow activation plan](https://www.tokenpost.com/news/technology/23346)