As title states. Does retroarch still require Mame bios files and if so where are they placed? Also what is the latest Mame bios pack version? 0.185?
if a game needs a BIOS with upstream MAME, it will need one with MAME-libretro. True BIOS files go in the ‘system’/BIOS directory, but some–notably neogeo.zip–are more like parent ROMs and, as such, go in the same directory as the games.
Bioses are part of a romset, same as FBNeo. If you are using mame2003 you need the bioses from a 0.78 romset, if you are using current mame you need the bioses from a 0.211 romset (or maybe still 0.210, not sure it was updated yet).
About their placement, i expect it follows the same rules as FBNeo : when you load a rom it search for bios/parent in current folder, then it fallbacks to libretro’s system_dir, if they do things right they’ll be searching in a dedicated system_dir subfolder by the name of the core first (having bioses at the root of system_dir is a bad practice, there are 9 cores searching for the same files but expecting different content…)