ARR
From Just Solve the File Format Problem
From Cubase 1.0 (1989) to [[CUBASE | Cubase VST 5.1] (2001) the file format used by Cubase was .all (Cubase song) and .arr (Cubase arrangement) files. It was only possible to open files on a Cubase version identical or newer than the version that saved the file. The upgrade to a new version of Cubase was not a big issue.