Citadel/UX
  | |
| Developer(s) | citadel.org |
|---|---|
| Stable release | 7.37
/ June 19, 2007 |
| Repository | |
| Operating system | Unix, Linux |
| Type | Groupware |
| License | GPL |
| Website | www.citadel.org |
Citadel/UX (usually referred to simply as "Citadel") is a collaboration suite (messaging and groupware) that is descended from the Citadel family of programs which became popular in the 1980s and 1990s as a bulletin board system platform. It is designed to run on open source operating systems such as Linux or BSD. Although it is still being used widely on bulletin board systems, in 1998 the developers began to expand its functionality to a general purpose groupware platform.
In order to modernize the Citadel platform for the Internet, the Citadel/UX developers added functionality such as shared calendars, instant messaging, and built-in implementations of Internet protocols such as SMTP, IMAP, Sieve, POP3, and GroupDAV. All protocols offer OpenSSL encryption for additional security.
Users of Citadel/UX systems also have available to them a web-based user interface which employs Ajax style functionality to allow application-like interaction with the system.
Citadel uses the Berkeley DB database for all of its data stores, including the message base.
The software is open source, and released under the GPL license. Its developers assert that Citadel is one of the few products in this category that is built as end-to-end free software, while most others offer only a feature-limited free version, choosing instead to require a paid license for their full-featured versions.