download an old version of a theme

Hi, i need change a theme that i use in my web. I used a theme named cupertino in version 1.8.18.

Now i need change it to use other edited but i can´t download the version 1.8.18 of my new theme, i only can download in version 1.9 or higgest...

can somebody help me? i don´t want change every code, i want use the same but with a new theme wich i've edited.