As a discontinued product, MSM release packages are no longer available.
The last MSM pre-End-Of-Life production release was v2.3.14
The Final End-Of_life release (made available to customers when the product was discontinued) was v3.1.1
The authoritative source for Mach3 release and updates is the MachSupport web site.
– this release has proven to be a popular, stable release for use with MSM 1.x.