ACPI administration advocacy advocacy advocacy opinion alsa amarok apache apple apt aptitude archive audio audo authentication automount avi awk backup bash BIOS boot browser business bzip cache calendar calibre cdr cdrecord censorship commandline computerscience console convert cron cut database date debian degree design desktop development disk dpkg dvd economics education emacs email europe exim faad ffmpeg file files firefox firewall flash foss freedom ftp fun fuse git gnumeric graphics grep growisofs grub gtkpod gzip hardware hardware html icedove idiocy image imagemagick images installation ip iphone ipod iptables iso itunes ivman kde kernel keyboard knoppix lame laptop latex libreoffice linux locale lockin locking longlines lsof m4a microsoft mimetypes minitab mogrify mount mp3 mp4 mplayer multimedia music mysql network nfs nfs4 nmap openbox openfiles openoffice opinion opinion orgmode partition pdf pdftk perl php podcast politics pomodoro ports postgresql print printing privacy process programming rant remote rhythmbox rss rsync rxvt scp screengrab screenshot script scripting scsi security sed server services shell siteadmin sitenews sitesoftware skype skype slackware sound sox spam spreadsheet ssh statistics subversion sudo svk swap t23 t43 tar terminal tex text thinkpad thunderbird time timer timezone ubuntu udev upgrade usb usbmount users uuid versioncontrol vfat video vnc windows wine wordpress wordprocessing X40 xwindows xwindows youtube
Upgrading is always one of the most fearful things in the world. Big upgrades generally tend to break somewhere. That's why I have been putting off the upgrade from exim3 to exim4, even though the developers say that exim3 is deprecated and everyone should move over to exim4.
The last server I needed to upgrade was a server running Debian stable. Real email goes through the server and if the upgrade broke, then all sorts of email might be bouncing. Sunday morning, therefore, seemed to be a good time to do it.
apt-get update apt-get install exim4
But I was pleasantly surprised. The exim4 installer recognised that I was using a smarthost and seemed to read options from the existing exim3 configuration file. The new exim4 configuration file was properly set up. All email seems to be routed where it should be. So, don't be afraid of upgrading from exim3 to exim4 if you are using Debian stable.
Update: Of course there was one problem. There's always a problem. The installer decided that the server only wanted to listen on the local interface for email, that is on 127.0.0.1. No email coming from outside could therefore be delivered. I don't know why the installer wanted to do this, but it did. I had to fix the dc_local_interfaces option in /etc/update-exim4.conf.conf. Now, it seems to work.