Solana Sets October 21 for Alpenglow Upgrade Targeting 150-Millisecond Finality

Key Takeaways

• Solana plans to launch its Alpenglow upgrade on October 21, aiming to speed up transaction finality to roughly 150 milliseconds, down from 12.8 seconds.
• Alpenglow will replace TowerBFT and shift validator voting off the main blockchain.
• For the migration, validators must use Agave 4.3.0, while operators running Firedancer and Frankendancer will need to switch software temporarily.

Solana has scheduled its Alpenglow consensus upgrade for Wednesday, October 21, a major upgrade that will speed up transaction finality to roughly 150 milliseconds by changing how the computers running the network agree on payments.

The Solana Foundation’s upgrade guide places activation in epoch 1064, which is expected to begin around 15:00 UTC. An epoch is a period during which validators are assigned their network responsibilities by Solana.

The timing remains approximate because epoch boundaries can drift with network slot timing.

— Anza (@anza_xyz) Oct 13, 2026

Read More: Solana Nears 200-Millisecond Block Times as Network Upgrade Enters Final Stage

Faster Settlement Through New Voting System

Alpenglow replaces TowerBFT’s voting and finality logic with Votor, according to developer Anza. The protocol targets roughly 150-millisecond finality under normal network conditions.

Validators will exchange votes directly and combine them into certificates. This will allow blocks to become final after one or two voting rounds.

Under the existing system, the target is about 12.8 seconds. This describes transaction finality, instead of the interval between blocks, which Solana reduced separately to 200 milliseconds.

Anza has cautioned that some nodes might receive finalization information later. This depends on how they connect to participating validators. The headline target therefore does not guarantee identical response times for every service.

Validators Prepare for Activation

Validators must prepare for the transition by running software based on Agave 4.3.0.

This is because alternative validator clients Firedancer and Frankendancer will not support the initial migration; their operators will need to temporarily switch programs.

Wallets, transaction signing, and existing programs continue operating as before. Data providers should update systems that process blocks and validator votes.

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