The term "new" is a marketing tactic used by repackers. Since ArtCAM 2018 is abandonware (no longer updated by Autodesk), there is no "new" official version. However, crackers frequently repack the same build (typically version 2018.0.0 build 181) with different "verified" hashes to convince users it is a fresh, bug-free release.
Imagine carving a 4-foot by 8-foot piece of walnut. You are 6 hours into a 10-hour carve. Suddenly, the "portable" ArtCam crashes because a registry entry is missing or a virtual DLL fails. You lose your toolpath. Unlike legitimate software, you cannot call support or recover the file.