There are things here that can seem obvious to the experienced and baffling to the newbie. If this is how I got caught up then I think I know the confusion here.
The version number is not the same as the year for the release. Visual Studio 2017 is version 15. If you open Visual Studio 2017, go to help, then the about screen you'll see.
As for the build configuration incompatibility stuff it's definitely common and can be frustrating. Sometimes it's an obvious mismatch (trying to compile a 32 bit program while including 64 bit SFML) but sometimes it's a little deeper or more confusing than that. Generally if there are strange issues like this VS is where you should look first.
I've encountered issues when Visual Studio is working and building fine, I update VS, then it insists the build configuration is incompatible. I came to find out somehow I had to create a new build profile with exactly the same values and name as the old one to make it work.
In my experience Visual Studio can be incredibly buggy with solution and project files.