courier-maildrop software package provides Courier mail server - mail delivery agent [transitional package], you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install courier-maildrop
courier-maildrop is installed in your system.
Make ensure the courier-maildrop package were installed using the commands given below,
$ sudo dpkg-query -l | grep courier-maildrop *
You will get with courier-maildrop package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | |
| Package | courier-maildrop |
| Version | 2.8.4+0.76.3-1 |
| Description | Courier mail server - mail delivery agent [transitional package] |
| Sub Section |