I’ve done the “upgrade” on three Macs. In each case, it went very easily and the application notified me when everything was done (in one case, it was almost instantaneous). You end up with a symlink from the old Dropbox location to the new one, so the files are easy to access. If you were using external symlinks to individual files in your Dropbox, then those would need updating. Otherwise, it was pretty painless. It helps that I didn’t have the files on an external drive. I understand that the process isn’t quite so easy if that’s the case.