By Gabriel Partos
BBC south-east Europe analyst
The head of the United Nations Mission in Kosovo (Unmik), Soeren Jessen-Petersen, is in Belgrade for talks that are expected to focus on security, decentralisation and minority protection in the UN-administered province.
The Serb minority and their representatives have been boycotting Kosovo's institutions since widespread riots last March, which set back progress towards the consolidation of democracy and the rule of law.
Mr Jessen-Petersen (right) is unlikely to end the boycott
There is now just six months or so left before the UN Security Council is due to review whether Kosovo has achieved the required democratic standards to warrant the opening of talks on Kosovo's long-term status.
It is Mr Jessen-Petersen's second visit to the Serbian capital since he took over as the head of Unmik in August. Much has changed during those five months.
Elections in late October passed off peacefully - much to the relief of the UN. And in December a new government was formed under Prime Minister Ramush Haradinaj - a controversial choice because he had previously been questioned by investigators from the international war crimes tribunal for the former Yugoslavia, suggesting that he might be among the last group of individuals to be indicted.
Meanwhile, Mr Jessen-Petersen has been pressing on with plans to devolve power in Kosovo to the municipal institutions as part of a decentralisation drive.
One, crucial, thing, though, hasn't changed: the continuing boycott by the vast majority of Serbs and their representatives of Kosovo's institutions. That boycott goes back to the violence in March, which led to several thousand Serbs fleeing Kosovo, and to the decentralisation plans that are about to be implemented.
These plans do not accord with Belgrade's own blueprint for a much greater degree of self-government to be introduced for Kosovo's Serb minority.
The boycott has been backed by the Serb Prime Minister, Vojislav Kostunica, and by the majority of Belgrade's political establishment. Mr Haradinaj's election last month as prime minister only hardened Serb opposition to renewed participation in Kosovo's institutions, because Serbs regard him as a war criminal.
And it is unlikely that Mr Jessen-Petersen's visit now will persuade Belgrade to change its mind over the boycott.
If Mr Haradinaj were to be charged in the coming weeks by the Hague tribunal, that could lead to a shift in Serb attitudes. On the other hand, an indictment would almost certainly create problems among Kosovo's ethnic Albanian majority, who view Mr Haradinaj as a war hero.
At the very least, there would be a government crisis while a replacement was found.
For his part, Mr Jessen-Petersen admitted during a recent visit to London that if an indictment were issued against Mr Haradinaj, it would lead to problems.
"If, indeed, there were to be an indictment, it could lead to a certain delay in our way forward," he said. "But I don't think that it would disrupt it in any major way."
During his talks in Belgrade Mr Jessen-Petersen will once again explain patiently why he thinks Serbs should rejoin the negotiating process on Kosovo.
He will make the point that it would be much better for Serbs to be part of the process of reforms and to argue their case than to stand by while measures, such as decentralisation, are introduced without their voice being heard.
But with a change of heart in Belgrade unlikely - at least at this stage - the planned pilot projects for decentralisation will probably go ahead in the coming weeks without reference to the Serb standpoint.
Ramush Haradinaj's election as Kosovo's PM was controversial
Decentralisation remains a key part of the drive to consolidate democracy and the rule of law while improving the security environment and enhancing the protection of the Serb and other minorities.
What progress is made in these areas will form the foundation for the UN Security Council's assessment of conditions in Kosovo, due in the middle of this year - six years after the UN took control of Kosovo's administration.
If that assessment is positive, talks will get under way, perhaps early next year, on Kosovo's long-term status.
Kosovo's Albanians are hoping that such talks will lead to their independence - a prospect Belgrade doesn't even want to contemplate in public.
The current Serb boycott may, in fact, turn out to be a dress rehearsal for non-participation in the future status talks.
That would be an option for the Belgrade leadership of the time if it decides that it wouldn't want to consent to an outcome that might amount to the loss of Kosovo.