You can find community-uploaded Serbian and Croatian subtitles (which are often compatible for Serbian speakers) on dedicated subtitle websites:
The official Serbian title for the movie Mamma Mia! Here We Go Again is . typically including multiple language tracks.
: Offers Croatian subtitles for the 2018 release that are frequently used by Serbian viewers. typically including multiple language tracks.
: The DVD version with the "sing-along" feature is available for purchase in Serbia , typically including multiple language tracks. typically including multiple language tracks.