All you have to do it name the sister "Imouto" (I think other names work, too) and you get the "old" version.
It's readily available information.
Viewing post in A Simple Life with My Unobtrusive Girl comments
I don't understand what you mean. Do you mean that there is a system in the game that makes it to where if you name her specifically "Imouto" that that changes the game to be patched as if it was never changed in the first place? Or do you think just changing the name to "Imouto" is going to just make the game feel like before it was changed because the main character is going to refer to her that way? Because if it's the former, then as I said before, I have not been keeping up with this game and have never seen this "information that is readily available," and if it's the later; then you're mistaken if you think just changing the character name to make the make character refer to her as "Imouto" is enough to make it the "old" version of the game when the game itself (all I mean is the version before the payment processors came after itch and steam) is going to refer to her as otherwise when not saying her name.