“The core of Horde includes the Horde Application Framework, and
PHP Web application framework that is used to develop the family of
groupware applications for messaging, time keeping and contact
management, among others.“Horde 4 makes more use of the PHP Extension and Application
Repository and installing and updating Horde apps has been
simplified with its own PEAR server.“There some 90 applications and modules in the Horde ecosystem,
covering everything from groupware to session management and
integration with third-party Web services.“Horde’s flagship applications, IMP for e-mail and Kronolith for
calendaring, has received significant updates including new Ajax
interface.”