The Holy See said the new pope is set to keep Mr Francis’s top employees in the Vatican in place for the time being.
U.S. President Donald Trump, who clashed repeatedly with the pope about immigration, said he and his wife would fly to Rome for the service.
Pope Francis had officially recognised a second miracle attributed to Acutis and approved his canonisation.
The Catholic leader said the former pope, born Karol Wojtyla in Poland, was “these days the object of insulting and unfounded insinuations.”
Mr Guterres described the late Pope Benedict as “one of the leading academic theologians of our time”.
On October 25, the 85-year-old religious leader will pray for peace at the Colosseum in Rome with representatives of other religions.
