dovecot - Nov 2011 - 2.0.16 - auth with vpopmail won´t work anymore

Hi,

after upgrading from 2.0.15 to 2.0.16 authentication with vpopmail won?t 
work anymore.

2.0.x and 1.2.x works (this output is from 2.0.15):

Nov 28 18:29:21 mail dovecot: auth: Debug: auth client connected (pid=3855)
Nov 28 18:29:21 mail dovecot: auth: Debug: client in: AUTH 1 PLAIN 
service=imap secured lip=10.114.57.11 rip=10.114.57.11 lport=143 
rport=37693 
resp=d3NjaG9lbGxlckBodGwtcGVyZy5hYy5hdAB3c2Nob2VsbGVyQGh0bC1wZXJnLmFjLmF0AGRpYWJsbw=Nov
28 18:29:21 mail dovecot: auth-worker: Debug:
vpopmail(wschoeller at htl-perg.ac.at,10.114.57.11): lookup user=wschoeller 
domain=htl-perg.ac.at
Nov 28 18:29:21 mail dovecot: auth: Debug: client out: OK 1 
user=wschoeller at htl-perg.ac.at
Nov 28 18:29:21 mail dovecot: auth: Debug: master in: REQUEST 4001103873 
3855 1 7a21a4d39cc6b187b3b14dc4cfbf077a
Nov 28 18:29:21 mail dovecot: auth-worker: Debug: 
vpopmail(wschoeller at htl-perg.ac.at,10.114.57.11): lookup user=wschoeller 
domain=htl-perg.ac.at
Nov 28 18:29:21 mail dovecot: auth: Debug: master out: USER 4001103873 
wschoeller at htl-perg.ac.at uid=89 gid=89 
home=/var/vpopmail/domains/htl-perg.ac.at/wschoeller
Nov 28 18:29:21 mail dovecot: imap-login: Login: 
user=<wschoeller at htl-perg.ac.at>, method=PLAIN, rip=10.114.57.11, 
lip=10.114.57.11, mpid=3856, secured
Nov 28 18:29:21 mail dovecot: imap(wschoeller at htl-perg.ac.at): 
Disconnected: Logged out bytes=29/405
Nov 28 18:29:21 mail dovecot: auth: Debug: auth client connected (pid=3858)


2.0.16 doesn?t work:

Nov 28 18:43:15 mail dovecot: auth: Debug: Loading modules from 
directory: /usr/lib/dovecot/auth
Nov 28 18:43:15 mail dovecot: auth: Debug: auth client connected 
(pid=27392)
Nov 28 18:43:15 mail dovecot: auth: Debug: client in: AUTH 1 PLAIN 
service=imap secured lip=10.114.57.11 rip=10.114.57.11 lport=143 
rport=42768 
resp=d3NjaG9lbGxlckBodGwtcGVyZy5hYy5hdAB3c2Nob2VsbGVyQGh0bC1wZXJnLmFjLmF0AGRpYWJsbw=Nov
28 18:43:15 mail dovecot: auth-worker: Debug: Loading modules from
directory: /usr/lib/dovecot/auth
Nov 28 18:43:15 mail dovecot: auth-worker: Debug: 
vpopmail(wschoeller at htl-perg.ac.at,10.114.57.11): lookup user=wschoeller 
domain=htl-perg.ac.at
Nov 28 18:43:15 mail dovecot: auth-worker: 
vpopmail(wschoeller at htl-perg.ac.at,10.114.57.11): Password mismatch
Nov 28 18:43:15 mail dovecot: auth-worker: Error: 
md5_verify(wschoeller at htl-perg.ac.at): Not a valid MD5-CRYPT or 
PLAIN-MD5 password
Nov 28 18:43:15 mail dovecot: auth-worker: Error: 
smd5_verify(wschoeller at htl-perg.ac.at): SMD5 password too short
Nov 28 18:43:15 mail dovecot: auth-worker: Error: 
ssha_verify(wschoeller at htl-perg.ac.at): SSHA password too short
Nov 28 18:43:15 mail dovecot: auth-worker: Error: 
ssha256_verify(wschoeller at htl-perg.ac.at): SSHA256 password too short
Nov 28 18:43:15 mail dovecot: auth-worker: Error: 
ssha512_verify(wschoeller at htl-perg.ac.at): SSHA512 password too short
Nov 28 18:43:15 mail dovecot: auth-worker: Warning: Invalid OTP data in 
passdb
Nov 28 18:43:15 mail dovecot: auth-worker: Debug: 
vpopmail(wschoeller at htl-perg.ac.at,10.114.57.11): CLEARTEXT(mypassword) 
!= '', try OTP scheme instead
Nov 28 18:43:17 mail dovecot: auth: Debug: client out: FAIL 1 
user=wschoeller at htl-perg.ac.at
Nov 28 18:43:17 mail dovecot: imap-login: Aborted login (auth failed, 1 
attempts): user=<wschoeller at htl-perg.ac.at>, method=PLAIN, 
rip=10.114.57.11, lip=10.114.57.11, secured

Dovecot -n:
# 2.0.15: /etc/dovecot/dovecot.conf
# OS: Linux 2.6.36-gentoo-r8 i686 Gentoo Base System release 1.12.14
auth_debug = yes
auth_debug_passwords = yes
disable_plaintext_auth = no
first_valid_uid = 89
listen = *
mail_location = maildir:~/.maildir
namespace {
   hidden = no
   inbox = yes
   list = yes
   location    prefix = INBOX.
   separator = .
   type = private
}
passdb {
   args = webmail=127.0.0.1
   driver = vpopmail
}
service auth {
   user = root
}
ssl_cert = </etc/ssl/dovecot/server.pem
ssl_key = </etc/ssl/dovecot/server.key
userdb {
   driver = vpopmail
}



Just a wild guess - but is it possible that the reason could be found here:
http://hg.dovecot.org/dovecot-2.0/rev/b99da8b1ecef

Thanks for any suggestions.

Best regards,
Werner