Why does GOG say that it Works on Windows 8 and 10 but Steams says it works on 7, 8 and 10 (64 Bit)?

For some of us, ''Real time strategy'' isn't a thing, due to poor co-ordination, slowness, etc.
A turn by turn game, by one of my favorite authors and a favorite book, and I'm there. Playing the bugs with them at a relative10x speed though? They are bad enough in the books at normal :p