Just sharing my experience with this update. I'm aware that there
have been quite a few folks with troubles as reported on the dovecot
mailing list.
My own experience was
a) dovecot itself worked with no problems at all.
b) I did however have pigeonhole failing which was perplexing -
however restarting dovecot a second time got the sieve working and over
the last half day or so everything is working well. I have noticed for
users with no sieve script there remained some fails running the default
sieve script. I am recompiling that script (sievec) manually to see if
that helps.
gene