North Korea has raised the minimum age for joining the ruling Workers’ Party of Korea (WPK) from 18 to 20, according to a new analysis of the party’s updated rulebook, a change that could delay any formal leadership role for Kim Jong Un’s daughter.

The change was among several revisions adopted at the Ninth Party Congress in February to strengthen the party’s organization and institutionalize Kim’s “monolithic” leadership, according to a report published Thursday by the Institute for National Security Strategy (INSS), a think tank affiliated with South Korea’s National Intelligence Service (NIS). 

Kim’s daughter — whom the NIS believes