You should determine the version of Arc you currently have. You can do this by starting Arc on your machine. Text similar to the following will appear in the text window:

XLISP-PLUS version 3.04
Portions Copyright (c) 1988, by David Betz.
Modified by Thomas Almy and others.
XLISP-STAT Release 3.52.17 (Beta).
Copyright (c) 1989-1999, by Luke Tierney.
; updates.lsp version of August 8, 2001
; Arc 1.03, rev Aug, 2000, (C) 1999-2000, R. D. Cook & S. Weisberg.
; Type (help 'copyright) to see the license agreement.

• If the version number of Arc is a number lower than 1.06, you need to get a new version of Arc by selecting one of the links below, and then following the directions. You should install Arc into the same directory you used before; none of your personal files will be changed, but program files will be updated.
  • Macintosh.
  • MS Windows.
  • Linux/Unix.
• If you have version 1.06 of Arc, you can check to see if there is a more recent updates file. If you encounter a problem with Arc the most recent updates file may fix the problem.