How to pg_upgrade an 8.4.3 Installation

Hi!

I have an additional question about the pg_upgrade bugfix described in
http://wiki.postgresql.org/wiki/20110408pg_upgrade_fix

Suppose I have an 8.4.3 installation somewhere which I want to upgrade to
9.0.4.

Can I simply use the 9.0.4 pg_upgrade on this since the bug has been fixed
in 9.0.4, or would I first have to upgrade the 8.4 installation to 8.4.8?
If so, would be it enough to simply replace the 8.4.3 binaries with 8.4.8
versions, or would I have to start and stop the server once?

The reason I am asking this is because I am going to do the upgrade
automatically in an installer, and if I could avoid the double upgrade, it
would simplify things.

Regards,
--
Nils Gösche
"Don't ask for whom the <CTRL-G> tolls."