Licq

LICQ, often written licq, is an open-source client for the ICQ instant messaging protocol. It was one of the early ICQ clients for Unix-like systems and gained popularity among Linux users in the late 1990s and early 2000s. The project aimed to provide a feature-rich, extensible client with a modular design and separate user interfaces.

The client offered core messaging functionality such as a contact list, presence information, and the ability to send and receive instant messages. It supported multiple ICQ accounts and exchange of basic presence data, with options for logging conversations and managing buddy lists. Licensing for Licq aligned with free and open-source software principles, and the project emphasized extensibility through plug-ins and modular components.

Technically, Licq was implemented primarily in C++ and deployed GUI front ends for various environments, including Qt- and GTK-based interfaces, allowing users to choose a preferred desktop integration. Its architecture was designed to be extendable through plug-ins, enabling additional features without altering the core protocol code.

Development history and status: development of the original Licq project slowed during the 2010s, and the project became effectively inactive for routine maintenance. While the original repository and code remain available, several forks and derivative projects have appeared, and Licq is no longer a mainstream ICQ client. In contemporary usage, users seeking ICQ functionality more commonly turn to other clients or gateway solutions.

See also: ICQ protocol, Pidgin, Adium, Miranda IM.