BELGRADE—Bosnia’s outgoing international peace overseer decreed amendments to its criminal code on Friday to allow jail terms for the denial of the 1995 Srebrenica genocide, a frequently expressed view among nationalist Serbs. The decree by High Representative Valentin Inzko sets jail terms of up to five years for anyone who “publicly condones, denies, grossly trivializes or tries to justify” the genocide or war crimes committed during Bosnia’s 1992–95 conflict. In July 1995, Bosnian Serb forces seized the UN-protected enclave of Srebrenica in the country’s east and killed about 8,000 Bosnian Muslim men and boys they took prisoner. It was the worst atrocity in Europe since World War Two and was judged an act of genocide by two international courts. Inzko, whose 12 years in office ended on Aug. 1 when he will be replaced by Germany’s Christian Schmidt, can impose laws and fire officials under the 1995 peace treaty that …