ARR

From Cubase 1.0 (1989) to 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. Later Cubase software used CPR (for projects).