Why version matters MAME's drivers and ROM mappings change over time. A ROM set tied to 0.250 ensures compatibility: the emulator's drivers reference the exact filenames, sizes, and checksums that the 0.250 release expects. Using a mismatched ROM set with a different MAME version can lead to missing-game errors, incorrect ROM loads, or games failing to run because of renamed or reorganized ROMs, changed parent/clone relationships, or updated BIOS handling. Preservationists and archivists often keep dated ROM sets so they can reproduce behavior precisely as of that codebase.