Can one go from 4.3.1 or 2 or 3 back to 4.2.5? Seems to be the last basecamp that worked. Is the database the same? I think that was the last version that put my waypoints in categories by the lists they were it.
Should be although I've never tried it, but you will need to juggle with the database ... 4.3 is stored in a folder named 4.3 whereas 4.2 is called 4.2 :)
Having said that 4.3 is working fine for me, what's not working for you? If it's simply the way categories now work the change came about because of the numerous complaints about the way it used to work, guess you prefer the old way.