Its a patch that you download and just copy to the game folder and it also works on all versions. The website has instructions to install it.
https://lewdpatcher.com/game/my-new-family
Theres the link to it.(I hope i can post a link here)
Content wise it basically makes the MC's Landlord his mom and here daughters and Sister your family. Gives and extra fetish to it and makes the game make more since in my opinion.