Big Business aims to run on all current computers. It was not possible to fix Big Business 11 to work on newest Macs, but it is possible to fix Big Business 12 to work on Old Windows, including Windows 7, Windows 8.1, and Windows Server 2012, which are still wildely deployed but may be losing support from Microsoft soon.
This Solution will provide details. (6969)
Big Business 12 is being fixed to run on Windows 7, Windows 8.1, and Windows Server 2012. This may also help with Windows 10 earlier Updates.
The Latest Release of Windows should be used if possible. For Windows 7, for example, this is Service Pack 1 (6.1.7601).
In any event it is possible that there may be issues such as Printing or Security, that will not be fixed or that Big Business Client for Windows 7 will no longer work.
The Windows Release Information linked here includes Previous Versions and some known issues, like TLS, which is modern security used by Big Business connections and increasing not "backwards-compatible" with older methods.