Solana’s improvement proposal SIMD-0337 introduces a block tagging feature that implements a fast leader handover mechanism in Alpenglow. This technology allows leaders to begin block production immediately based on the expected parent block, without waiting for confirmation, reducing block production time by approximately 120 milliseconds and improving Inter-Block Reliable Latency (IBRL) by about 7.5%. The new mechanism is realized through two tags: BlockHeader and UpdateParent, ensuring security against malicious actions while maximizing network throughput. Complete technical details have been published on GitHub.