Kabila, 47, was due to step down at the end of 2016 after reaching the end of his constitution-limited two terms in office.
But he stayed on, invoking a caretaker clause in the constitution that enables a president to stay in office until his or her successor is elected.
The elections were postponed until the end of 2017 under a deal brokered by the powerful Catholic church — and then again until 2018, when Kabila eventually confirmed he would not run again.
The delay sparked protests that were bloodily suppressed, causing dozens of deaths and sparking an outcry from western nations and the UN.
One of the figures behind the crackdown is Kabila’s hand-picked successor, Emmanuel Ramazani Shadary, a hardline former interior minister.
Critics of the president say Shadary will be manipulated from behind the scenes or set the stage for Kabila to make a comeback.