[Dovecot] upgrading: should I and what will change?

I've been running dovecot 0.99.11 with postfix and postgresql in a production environment with about 25 real users and a couple hundred aliases split over a few domains for nearly a year now. No problems of any kind that I have noticed. Should I upgrade to the latest dovecot? What changes, if any, will I have to make? I've looked through the archives for a couple months without seeing much, and I don't see anything specific in the docs about upgrading.

-Joshua <><