Different editions of single app

I have an application with different editions: Basic, Standard and Pro. Do I have to create three different projects with wyBuild or can it create a patch by comparing Basic with Basic, Standard with Standard and so on in a single project?

It depends. If the different editions use different files, then you'll need to use separate project files. If the different editions all use the same files and are differentiate by, say, custom license fields used in your licensing, then you can use the same wyBuild project file for all editions.

All of the editions consist of a single exe file but the files are different between editions (they are built from one solution but with #if for conditional compiling. I guess I will need three different projects.