From reading on Microsoft's site it sounds like it is necessary to dual sign your application to include both sha1 and sha256 if you want your program to run on Windows 7 and Windows 8/10.
https://msdn.microsoft.com/en-us/lib...=vs.85%29.aspx
https://knowledge.symantec.com/suppo...int&actp=PRINT

As an experiment, I code signed a utility with only sha256. It ran fine on a Windows 7 machine.
What are the downsides to only code-signing with sha256?
Is it really necessary to also include sha1 if your program is running on Win 7?

TIA,
Rick