Some of the old software before 2010 may not be able to install/run normally on x64 or Windows 10 systems. Be aware of it before purchasing it.
Windows 3.1 Software Development Kit (SDK) can create programs for Windows 3.0 and Windows 3.1 complete with Windows help files and setup programs. It has a DOS-based installation program and it only runs on Windows 3.1. And while many of the development tools are Windows-based, there are many DOS-based tools as well, including the Resource Compiler that creates the actual Windows executable programs. It is based on the C and C++ programming languages.