* Robert Heller:
This is the reason *RedHat* Enterprise Linux is never recomended to
upgrades across major versions. The recomended practice is allways a fresh
That's mostly because Red Hat does not want to support such
installations of unknown genealogy. Technically, in-place upgrades
for most systems work, as long as you take care of the usual offenders
(e.g., Berkeley DB, as Michael pointed out, and PostgreSQL).