Workshop4 is a Windows Only product. It is compatible with Windows XP to Windows 10 (Windows 7 or higher is recommended). Note that some older OS's such as Windows ME and Vista have not been tested for some time due to availability, however should still work.
It is possible to run Workshop4 under a virtual machine on Linux or Mac, however it is not officially supported. It is up to the user to set this up. Many customers have had success running Workshop4 under a VM, but is not something we can support officially.