Jane may correct me, but I believe the "Clean Living People" plugin doesn't
rely on the Private and Living flags, although it will use them if present.
It can (optionally) assume that people born after a year you specify and
without a death date are living. It does need to be run on a copy of your
project, as it modifies the data. And I'm not certain that it has been
updated for compatibility with Version 6 yet.