[NTG-context] imposition: getting to the last page of a booklet

Greetings, I would like to use the nextquadruple and beforequadruple pagebreakhandlers described at the bottom of the wiki's imposition page. However, the examples complain of an error invoking the \installpagebreakhandler command. The wiki page was last updated nearly four years ago. Is anyone using updated versions of these? -- With kind regards, Michael