You can install LispWorks 8.0 in the same directory as previous versions such as LispWorks 7.1. This is because most of the 8.0 files are stored in a subdirectory called lib/8-0-0-0.
Binaries produced by cl:compile-file in previous versions of LispWorks do not load into a LispWorks 8.0 image. You must recompile all your code with the LispWorks 8.0 compiler.
Release Notes and Installation Guide - 01 Dec 2021 19:38:49