Tue. Jul 7th, 2020

Kamailio SIP Server v5.3.5 releases, The Open Source SIP Server

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Kamailio is an open source implementation of a SIP Signaling Server. SIP is an open standard protocol specified by the IETF. The core specification document is RFC3261.

The Kamailio SIP server is designed for scalability, targeting large deployments (e.g. for IP telephony operators or carriers, which have a large subscriber base or route a big volume of calls), but can be also used in enterprises or for personal needs to provide VoIP, Instant Messaging, and Presence. It is well known for its flexibility, robustness, strong security, and the extensive number of features – for more information, please see:


Kamailio development was started back in 2001 by Fraunhofer Fokus, a research institute in Berlin, Germany. At that time the project name was SIP Express Router (aka SER). In 2005, a fork named OpenSER was created, which was renamed to Kamailio in July 2008 due to trademark issues. Starting in the autumn of 2008, Kamailio and SER initiated the process to merge the two projects. After the merger was completed, it became the main name of the project, being better protected in terms of trademarks.

Changelog v5.3.5

a minor release including fixes in code and documentation since v5.3.4. The configuration file and database schema compatibility is preserved, which means you don’t have to change anything to update.