On August 5, the network activated a slot time reduction from 400 milliseconds to 350 milliseconds on testnet, kicking off a phased upgrade that aims to eventually cut slot duration in half. Each 50ms reduction can only activate after receiving supermajority endorsement from validators, meaning roughly two-thirds of staked validators need to explicitly opt in before anything changes. The bigger picture for Solana in 2026The mainnet rollout of the Agave v4.2 client is expected around August 17. If slot time reduction is about producing blocks faster, Alpenglow is about making those blocks irreversible faster. Each subsequent 50ms reduction requires a fresh supermajority vote from validators, creating four distinct checkpoints where the upgrade’s momentum gets tested.