There was a download of MS4W 4.0.5 on the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The latest version of the software is supported on PCs running Windows XP/XP Professional/Vista/7/8/10/11, 32-bit.
According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software. Commonly, this program's installer has the following filename: cmd.exe. The program lies within Development Tools, more precisely Distribution. The most popular versions among MS4W users are 3.2, 3.1 and 3.0. This free program is an intellectual property of Mozilla.
From the developer:
The purpose of this package is to allow all levels of MapServer users to quickly install a working environment for MapServer development on Windows. It is also an environment for packaging and distributing MapServer applications.
You may want to check out more software, such as Violet, FSNavigator or InstallAWARE, which might be related to MS4W.