Solana is set to undergo a significant upgrade with the introduction of Alpenglow, aiming to achieve sub-second finality by 2026. This overhaul involves a complete re-architecture of its consensus mechanism, replacing Tower BFT and Proof of History with new components, Votor and Rotor. Votor will streamline the voting process, allowing blocks to be finalized within 1 to 2 confirmation rounds, reducing finality latency to 100-150 milliseconds from the current 12.8 seconds. The upgrade also includes Rotor, which optimizes Solana's block propagation by using staked-weight relay paths for efficient bandwidth use. This change is expected to enable block propagation in as little as 18 milliseconds under typical conditions. The Alpenglow upgrade will be rolled out gradually, with an initial launch expected between early and mid-2026.