Internet Messaging Program


The Internet Messaging Program or IMP is a webmail client. It can be used to access e-mail stored on an IMAP server. IMP is written in PHP and a component of the collaborative software suite Horde.
It is included with cPanel and Plesk installations as a webmail client. It often integrates email, calendar, address book, notes, tasks, filters and a newsreader with cPanel.
Internet Messaging Program is free and open-source software subject to the terms of the GNU General Public License.

Current features

Chuck Hagenbuch published a first version of IMP on Freshmeat in 1998. A constant stream of feature requests not all fitting for a webmail application led to the development of a more generic web application backbone: the Horde framework. The release of IMP 3.0 and Horde 2.0 was the first one with two truly separate components. Since then any deployment of IMP can only run on top of a Horde installation.
SAPO uses IMP to provide several million users with a webmail platform. The company also sponsored the initial development of the dynamic AJAX variant of IMP which was released as a separate package - named DIMP - with the release of Horde 3.2.
Support for mobile clients was provided within 2006 for the first time. At that time a WAP based mobile view was provided by a separate package called MIMP.
With the release of Horde 4.0 the three existing views were collapsed into the original IMP package again. In addition another mobile view for smartphones was added based on the jQuery Mobile JavaScript framework.