jkp@kvm:~$ sudo apt-get install exim4-daemon-light
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
  exim4-base exim4-config
Suggested packages:
  eximon4 exim4-doc-html exim4-doc-info libmail-spf-query-perl swaks
The following packages will be REMOVED
  postfix
The following NEW packages will be installed
  exim4-base exim4-config exim4-daemon-light
0 upgraded, 3 newly installed, 1 to remove and 0 not upgraded.
Need to get 0B/1,923kB of archives.
After this operation, 528kB of additional disk space will be used.
Do you want to continue [Y/n]? y
E: Could not perform immediate configuration on 'exim4-daemon-light'.Please see man 5 apt.conf under APT::Immediate-Configure for details. (2)