That is exactly what I said too.
This thread is beyond stupid as the notion of nationality didn't exist during the EU3 or EU4 timeline. Inhabitants of the lands in Bosnia didn't consider themselves Bosnian, Serbian or Croatian or whatever other contraption, they just considered themselves from that mountain valley, that village or town, that forest, or in service/in lands of x noble.
The Bosnia in the EU3/EU4 timeline however, can be considered a successor kingdom to Serbia, from a merely political perspective.