bbPress.org

Exactly, that is what I mean with a major update, if code is added or changed in the templates or css.
If that happens I will need to go through all changed templates and apply the edits to the updated templates or css.

For css that is easy, just add css and if needed do ! important to override (works 95% of the time)

For templates it will be adding additions, mostly html, again to the updated templates

and then put that all again in the theme folder