MySQL version 4.x considered OK or bad?

A guy here is installing RT, and he wants to install the latest version of
MySQL with it, that is, version 4.x rather than 3.x.

I seem to recall seeing here lately that this version won’t work with RT,
but all attempts to find the message I have in mind have failed so far. Can
someone confirm or deny that MySQL version 4.x works with RT?

Kendric Beachey