We are formally at version 4. Older versions are archived on TeamCity.
There are several flavors of ProteoWizard depending upon your intended use. If you are primarily interested in using the tools, the binary distributions for your platform are most likely what you want. If you are interested in using ProteoWizard as part of a software project you are developing, check out the code from our GitHub repository. Other packages are also on Teamcity.
Developers interested in building the ProteoWizard libraries for use in their own projects can build the repository with the .NET SDK, using build.bat on Windows or build.sh on Linux; the README describes the options.