While Serbia will take Kosovo’s independence lying down do not expect the Serbs in Kosovo to be passive. Serbs have made public declarations that they will form their own local government which will report to Belgrade and not Pristina. They may even push for reentry to Serbia using the same ethnic homeland logic which will grant Kosovo’s independence.
North Kosovo, the area north of the Ibar River, makes the easy place for Serbs to reunite with Serbia. Ethnic enclaves are islands of Serbs in a sea of Albanians. Most these are in the eastern section of Kosovo but will likely either remain holdouts or abandoned. Eventually Kosovo Albans will take these over. A majority Serb district in the south will provide temporary refuge for isolationist Serbs. The region will be an arguing point between Serbia and Kosovo over who has control of it. Look for Strpce to become a less violent but still intense Nagorno-Karabakh.
Identity will play the biggest role in if there is ethnic upheaval in an independent Kosovo. Kosovo’s leaders will have to forge a Kosovar identity which includes Serbs if they wish to keep the country whole. Limiting overt Albanian pride (like having a flag which is not 100% the same as Albania’s) and keeping Serbs protected from foreign Islamist radicals will be key.