Updating bogofilter

[Andrew]

I've been using bogofilter with evolution for a few months now.  I've
set up a few filters, one of which I use to teach bogofilter about spam
it doesn't pick up.  (Real slick, mind you. :)  That's version 0.15.5.2
and now 0.17 is out.  I'm thinking of upgrading but I had a few
questions first:

Does the updated bogofilter feature updated spam definitions, i.e. will
it be better at guessing my spam?
Assuming yes to the last question, is there a way of keeping my own
configuration files from 0.15, or should I start anew?

Sorry if this has been documented somewhere; I couldn't find it in the
man page, online, or in the doc folder.

Thanks,
Andrew