The "2021" designation in your search typically refers to a major update in the MAME (Multiple Arcade Machine Emulator) ecosystem and FinalBurn Neo. During this period, developers refined how the dl1425.bin interacted with HLE kernels to provide near-perfect sound without the heavy processing tax of LLE. Why You Need These Files in 2021 and Beyond
If you’re running into the notorious "dl-1425.bin NOT FOUND" dl1425bin qsoundhle 2021