Solana has activated its first mainnet slot-time reduction, lowering the target slot time from 400 milliseconds to 350 milliseconds, with the change set to formally take effect at Epoch 1020. Brennan Watt said some SDK constants, including DEFAULT_MS_PER_SLOT, have not yet been updated to the new value and will be changed in later releases. During the transition, applications that rely on SDK constants matching live mainnet conditions could be affected, and developers were advised to determine manually at the Epoch boundary when the feature becomes active. Watt said the longer-term plan is to put these parameters on-chain (stored on the network for client queries), but that transition issue is being accepted for now to roll out the reduction sooner.