Solana has applied its first consensus upgrade, Alpenglow, to the mainnet.

Cointelegraph reported on Oct. 21 that the upgrade aims to cut transaction finality from about 12.8 seconds to about 150 milliseconds, a 99 percent reduction.

Alpenglow is designed to replace Solana’s existing consensus model, TowerBFT. From a user perspective, it targets processing speeds where transactions are confirmed instantly. The Solana Foundation saw this goal as potentially leading to improvements in payments, trade settlement and application responsiveness.

The first phase of the upgrade is Votor. Votor focuses on lowering transaction finality to about 150 milliseconds by replacing the existing voting and finalisation mechanism with direct validator voting and a certificate-based system. In later phases, the block data distribution protocol Rotor is set to be introduced. Rotor is designed to replace the current Turbine.

The target figures were not immediately implemented even though the upgrade was applied to the mainnet. Solana’s mainnet transaction finality time shown on the Alpenglow dashboard that day was 6.6 seconds, and throughput was 4,721 transactions per second.

Anza, the upgrade’s research team, assessed Alpenglow as the biggest change since Solana’s launch. It also judged that if latency falls to about 150 milliseconds, it could compete with Web2 infrastructure in terms of responsiveness.

Alpenglow extends recent work to cut latency. Solana first reduced slot time in August for the first time since its launch, and has been pursuing a plan to roughly halve it to 200 milliseconds. The Solana Foundation explained that these steps would reduce network latency and increase confirmation speed. The fourth phase of that plan was completed in October.

Validators are set to begin developing the Agave 4.5 upgrade after Alpenglow. Its core is increasing the number of accounts supported in a designated transaction from 64 to 96. Agave 4.5 is currently under development, with application planned for December 2026.

The key point to watch is how stably the targeted 150-millisecond transaction finality time is implemented in the actual mainnet environment. Solana has entered a phase of overhauling its consensus structure, cutting slot time and pursuing follow-on protocol upgrades at the same time to adjust network responsiveness and processing structure.