4531
Completely crashes my install trashed the setups had to do a complete reinstall from backup
Depends on your system hardware compatibility.
Warp9 recommends 4517 which is ALSO a develpment version.
"Mach4 changed a bunch of internal registers (# vars) as of 4517, and requires ESS plugin 260 or newer since their change broke compatibility with the older ESS plugins. ESS plugin 259 and older will only work with Mach4 builds 4470 and older.
Please select one of the following recommended pairs of Mach4 and the corresponding ESS plugin:
1) Recommended: Mach4 Hobby version 4.2.0.4517 with ESS 260
1) Recommended: Mach4 Industrial version 4.2.0.4517 with ESS 260