Visual Studio 2015 Change target platform to windows 7
From MSDN:
Target Platform Version
[...]
To target Windows 7 or Windows Vista, use the value 8.1, since Windows SDK 8.1 is backward compatible to those platforms. In addition, you should define the appropriate value for _WIN32_WINNT in targetver.h. For Windows 7, that's 0x0601. See Modifying WINVER and _WIN32_WINNT.
To get additional target platforms (i.e. older Visual C compilers), install the respective older Visual Studio version(s) in parallel.
For instance, if you want to use Visual Studio 2017 in the GUI and want to build against VC2008 (msvc90), install Visual Studio 2008 in parallel to Visual Studio 2017. In VS2017, in the build settings, you can then select the "VC 2008" build target.
Also see:https://poweruser.blog/visual-studio-2017-compile-against-older-visual-c-c-runtimes-372519fe1400