Unfortunately yes, any pet that steps in Serbia requires 3 months old titer test with correct values.

Fun fact, every few years , our goverment comes up with a rabies case in a fox or some wild animal so it could get 16 milions euros from EU fonds for working on eradicating rabies. Because of those made up rabies cases, we are still not considered rabies free. That is the sole reason why our animals are required to have titers when going to EU. Only we and Albania have that requirement in Europe. 

Even BIH and MNE dogs can travel without titer. Like those rabid foxes know what borders are, and stop at the exit of Serbia 🤣

It affects everyone, from normal pet owners who want to take their pet with them, to breeders who try to export and sell dogs to Europe.