The final version of UBB.Classic was officially defunct when the first build of UBB.threads v7 was released on
October 5th, 2006. Styles and modifications for UBB.Classic v6 and UBB.threads v6 are not compatable with UBB.threads v7.
If you where interested in migrating your old data to UBB.threads v7 then you could hire a developer to create a style for you (screenshots of how various pages [category list, post list, and topic list pages primarily]) will aid in matching colors of the old style.