[Zope] Upgrading from 2.3.3 ---> 2.4.2 on Linux

[BZ]

I looked through a lot of the docs and changes but cannot find 
anything specific.

I have a very big 2.3.3 installation (with an entire copy to play 
with) but I am not sure the easiest way to go about the upgrade.

- I can install 2.4.2 just fine (it compiles and runs)

Should I build a clean 2.4.2 and move over all the stuff (a pain)?

Unpack 2.4.2 into the 2.3.3 directory and just build it over the old one?

What I would really like is the 2.3.3 --> 2.4.2 update file which 
seems not to exist?

Anyone have some hints before I spend more time banging my head against a wall?

BZ