My girlfriend has been nagging me to upgrade her theme to the latest Thesis 1.7. Since I am lazy to do actual work I decided to give it ago. I updated my site first to do some testing since both themes are running on Thesis as a base theme. Fortunately the upgrade was painless and only took me 10 minutes.
The only difference I noticed is that you have to put the layout.css from the previous Thesis theme inside your /themes/thesis/custom folder and set it to be writable (chmod 777). Then you’ll have to append a few lines of code to your custom.css file:
get rid of the #page background color:
.custom .full_width > .page {
background-color: transparent;
}
.custom #page {
background-color: transparent;
}
Remote the navigation formatting
.custom .menu {
border:none;
}
.custom .menu a {
border:none;
background-color: transparent;
}
.custom .menu a:hover {
background-color: transparent;
}
Of course these optional changes depending on your design. But aside from that your thesis theme will be good to go!

