So, now that I finally was able to successfully upgrade my Clearspace 1.2.0 install, I have stumbled upon another issue. Namely, how do you make customizations that can and will persist across upgrades? The theme + changes we had made locally all blew up when I upgraded to 1.8.0. Is there a document on how to make changes so they will work with future versions?
There is not a sure-fire way to make customizations that will always persist across upgrades. We usually try to not make changes that will affect user content like templates but sometimes such changes are made.
Your best bet is keep track of what files you have changed and test them with new releases of the product.