As a rule, you should always install afresh. Even keeping a profile can mess things up because the default files used to create one may have changed. Installing on top of the old only works when the list of files in the new version exactly matches the list in the old, so that everything gets overwritten. Problems arise when files in the old version are not part of the new because they don't get overwritten; in the case of components, that means they get registered and you enter the twilight zone of undefined behavior.
h~
