http://dovecot.org/releases/1.2/beta/dovecot-1.2.beta4.tar.gz
http://dovecot.org/releases/1.2/beta/dovecot-1.2.beta4.tar.gz.sig

This release fixes a memory corruption bug related to MODSEQ handling in
earlier v1.2 releases. Memory corruption means that it's a security bug
and possibly exploitable. MODSEQ code is new in v1.2, so v1.1 and older
releases are not affected.

Other than that, there is an ESORT bugfix and other fixes that were
added to v1.1 branch too.