If the subtitles are slightly out of sync when you play the movie, most players like VLC or BS.Player let you adjust the delay manually using shortcut keys (usually G and H in VLC).
: A massive international database. You can find "Serbian (Latin)" and "Serbian (Cyrillic)" options here. I, Robot subtitles Serbian
: Another reliable source that allows you to filter specifically for Serbian subtitles. It provides clear info on which movie file version the subtitle matches. If the subtitles are slightly out of sync