If you cannot find a specific Serbian file that fits your version, Bosnian or Croatian subtitles are typically over 99% identical and will be perfectly understandable.
Community discussions suggest that for classic dramas like Million Dollar Baby , "human-written" subtitles are far superior to auto-generated ones, which often fail to capture the film's heavy emotional nuances. Million Dollar Baby subtitles Serbian
On Netflix , you can check your profile's language settings to see if Serbian is available as a standard subtitle option. If you cannot find a specific Serbian file