Please show the complete timetable.

In short, you will need a new travel day if you change trains after midnight.

As @rvdborgt  said we net more details because when you change the trains matters :)

If after midnight you need a 2nd travelday :)

Thank you for your replies, here is a picture of the journey

Just to clarify if you swap train before midnight it’s only classed as 1 travel day? 

That is correct.

Thank you for your replies, here is a picture of the journey

 

11 mins connection in Serbia is pretty risky and note that there is not much in Rakovica maybe go till Belgrade and spend there asome time and take a later train or next day one :)

The tickets in Montenegro and Serbia are pretty cheap (If you have a flexipass save these traveldays as the tickets are cheaper as the value of a Travelday ) Podgorica - Belgrade is just 19.20€plus reservation :)

Here the Reservation fee´s for the Nighttrain Bar - Podgorica - Belgrade