I have followed Falko's guide in Howtoforge to create a good-working Postfix box. Unfortunately, it has not been upgraded since and I see amavis and spamassassin has released newer versions, along with other packages in the system.
The question is, I'm not sure if an upgrade would work out-of-the-box. I fear it would break some configuration and I would have to re-check it from the beginning. (It was 7-8 months ago and I don't want to go over configuration files after each upgrade).
To make certain, would letting debian upgrade itself with the command "apt-get upgrade" directly, hinder anything useless? I have already held back the kernel, mysql (client and server), postfix, postfix-mysql and postfix-tls packages from upgrades.
Or at least, could I upgrade spamassassin and amavis (and related packages) without problems?
The server is getting a lot of mails and in a remote office, so I don't want to risk it...
NOTE: The related packages installed on the server are:
courier-authda 0.47-4sarge4 Courier Mail Server - Authentication daemon
courier-authmy 0.47-4sarge4 Courier Mail Server - MySQL authentication
courier-base 0.47-4sarge4 Courier Mail Server - Base system
courier-imap 3.0.8-4sarge4 Courier Mail Server - IMAP server
courier-imap-s 3.0.8-4sarge4 Courier Mail Server - IMAP over SSL
courier-pop 0.47-4sarge4 Courier Mail Server - POP3 server
courier-pop-ss 0.47-4sarge4 Courier Mail Server - POP3 over SSL
courier-ssl 0.47-4sarge4 Courier Mail Server - SSL/TLS Support
libdbd-mysql-p 2.9006-1 A Perl5 database interface to the MySQL data
libmysqlclient 3.23.56-3 LGPL-licensed client library for MySQL datab
libmysqlclient 3.23.56-3 LGPL-licensed client development files for M
libmysqlclient 4.0.24-10sarge mysql database client library
libpam0g 0.76-22 Pluggable Authentication Modules library
libpam-modules 0.76-22 Pluggable Authentication Modules for PAM
libpam-mysql 0.5.0-6 PAM module allowing authentication from a My
libpam-runtime 0.76-22 Runtime support for the PAM library
libsasl2 2.1.19-1.5 Authentication abstraction library
libsasl2-dev 2.1.19-1.5 Development files for authentication abstrac
libsasl2-modul 2.1.19-1.5 Pluggable Authentication Modules for SASL
mysql-client 4.0.24-10sarge mysql database client binaries
mysql-common 4.0.24-10sarge mysql database common files (e.g. /etc/mysql
mysql-server 4.0.24-10sarge mysql database server binaries
openssl 0.9.7e-3sarge1 Secure Socket Layer (SSL) binary and related
php4-mysql 4.3.10-16 MySQL module for php4
phpmyadmin 2.6.2-3sarge1 set of PHP-scripts to administrate MySQL ove
postfix 2.1.5-9 A high-performance mail transport agent
postfix-doc 2.1.5-9 Postfix documentation
postfix-mysql 2.1.5-9 MYSQL map support for Postfix
postfix-tls 2.1.5-9 TLS and SASL support for Postfix
sasl2-bin 2.1.19-1.5 Programs for manipulating the SASL users dat