dovecot not configured to listen to any ports after intrepid->jaunty upgrade

I just reproduced the dovecot question on a similar amd64 upgrade. Note that before the upgrade, there exists /etc/dovecot/dovecot.conf and /etc/dovecot/dovecot.conf.bak that differ like so:

ubuntu@iijj-amd64:~$ diff -u /etc/dovecot/dovecot.conf{,.bak}
--- /etc/dovecot/dovecot.conf 2009-04-15 10:36:07.102008118 -0700
+++ /etc/dovecot/dovecot.conf.bak 2009-04-15 10:36:06.894000914 -0700
@@ -21,7 +21,7 @@
 # Protocols we want to be serving: imap imaps pop3 pop3s managesieve
 # If you only want to use dovecot-auth, you can set this to "none".
 #protocols = imap imaps
-protocols = imap imaps pop3 pop3s
+protocols = imap imaps

 # A space separated list of IP or host addresses where to listen in for
 # connections. "*" listens in all IPv4 interfaces. "[::]" listens in all IPv6

Asking debconf to diff the maintainer's version versus the installed version gives the following diff (note that there is no /etc/dovecot/dovecot-postfix.conf or /dev/dovecot/dovecot-postfix.conf for that matter):

--- /etc/dovecot/dovecot.conf 2009-04-15 10:36:07.102008118 -0700
+++ /usr/share/dovecot/dovecot.conf 2009-03-31 16:27:35.000000000 -0700
@@ -2,6 +2,17 @@

 # If you're in a hurry, see http://wiki.dovecot.org/QuickConfiguration

+# ------------------------------ WARNING -------------------------------
+
+# If there's a file /dev/dovecot/dovecot-postfix.conf, which is part of
+# dovecot-postfix package, it will be used instead of dovecot.conf.
+
+# Keep in mind that, if that file exist, none of the changes in
+# /etc/dovecot/dovecot.conf will have effect on dovecot's configuration.
+# In that case you should customize /etc/dovecot/dovecot-postfix.conf.
+
+# ------------------------------ WARNING -------------------------------
+
 # "dovecot -n" command gives a clean output of the changed settings. Use it
 # instead of copy&pasting this file when posting to the Dovecot mailing list.

@@ -21,7 +32,7 @@
 # Protocols we want to be serving: imap imaps pop3 pop3s managesieve
 # If you only want to use dovecot-auth, you can set this to "none".
 #protocols = imap imaps
-protocols = imap imaps pop3 pop3s
+protocols = none

 # A space separated list of IP or host addresses where to listen in for
 # connections. "*" listens in all IPv4 interfaces. "[::]" listens in all IPv6
@@ -85,11 +96,12 @@
 ## SSL settings
 ##

-# IP or host address where to listen in for SSL connections. Defaults
-# to above if not specified.
+# IP or host address where to listen in for SSL connections. Remember to also
+# add imaps and/or pop3s to protocols setting. Defaults to same as "listen"
+# setting if not specified.
 #ssl_listen =

-# Disable SSL/TLS support.
+# Disable SSL/TLS support. <doc/wiki/SSL>
 #ssl_disable = no

 # PEM encoded X.509 SSL/TLS certificate and private key. They're opened before
@@ -99,7 +111,9 @@
 #ssl_key_file = /etc/ssl/private/ssl-cert-snakeoil.key

 # If key file is password protected, give the password here. Alternatively
-# give it when starting dovecot with -p parameter.
+# give it when starting dovecot with -p parameter. Since this file is often
+# world-readable, you may want to place this setting instead to a different
+# root owned 0600 file by u...

As steve confirmed, the maintainer version of dovecot.conf was chosen during the upgrade. The default version of dovecot.conf shipped by the dovecot-common package comes with no protocol enabled (protocols=none).

Since the end user is prompted for a configuration file change during the upgrade process and can review the difference, I'll mark this bug invalid.