Yum upgrade?

[Bojan Smojver <bojan rexursive com>]

After I didn't have much luck with an upgrade of an FC5 box to FC6T3
(see: https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=206913), just
for kicks, I tried "yum upgrade" to a development tree. That failed with
a whole bunch of dependency problems, including things like e2fs*.
Similar situation existed between FC4 and FC5, also on x86_64.

Is "yum upgrade" something that's supposed to work between FC(n) and
FC(n+1) or not?

-- 
Bojan