imp software package provides virtual package provided by php-horde-imp, you can install in your Debian 8 (Jessie) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install imp
imp is installed in your system.
Make ensure the imp package were installed using the commands given below,
$ sudo dpkg-query -l | grep imp*
You will get with imp package name, version, architecture and description in a table
| Distro | Debian 8 jessie |
| Section | Virtual packages |
| Package | imp |
| Version | |
| Description | virtual package provided by php-horde-imp |
| Sub Section | virtual |