Kamailio v 4.2October 16, 2014,:
Kamailio (SER) SIP Server v4.2.0 has been released – this is a major release, bringing out a consistent set of new features as well as improvements to existing components.

Overview of new features in v4.2.0

(for more details see the wiki page)

  • ten new modules: evapi, db_mongodb, jsonrpc-s, kazoo, ndb_cassandra, ndb_mongodb, nosip, rtpengine (replacing rtpproxy-ng), tsilo, uuid
  • TCP-based event API controlled from configuration file
  • database connector for MongoDB
  • embedded JSON-RPC server
  • middle layer connector for Kazoo VoIP platform
  • no-sql configuration file connector for Cassandra
  • no-sql configuration file connector for MongoDB
  • ability to handle no-SIP messages via configuration file event routes
  • control module for RTPEngine application used for NAT traversal or encryption/decryption between plain RTP and WebRTC-SRTP
  • ability to add new branches to active transactions on-the-fly (e.g., as soon as a new REGISTER from callee arrives)
  • unique identifiers generator for usage inside configuration file
  • pool of generic worker processes
    • acc module can do asynchronous insert of records to MySQL servers
    • sqlops module can do asynchronous queries to MySQL servers
    • async can trigger immediate asynchronous execution of routing blocks
  • significant improvements to internal memory manager
  • create traffic limiting ‘pipes’ on the fly with pipelimit module
  • active calls tracking (dialog) can replicate local data and work with remote profiles
  • monitoring (via SIP keepalives) and managing active calls can use dedicated timer processes pool to cope better with heavy traffic
  • enhancements to remote registrations to allow reloading records from database; add, enable or disable a record at runtime via rpc commands
  • topology hiding can use server IP everywhere
  • mechanism to detect retransmissions in early phase of configuration processing without creating the heavyweight transaction structure
  • manage muli-part bodies: set, remove or append parts
  • ability to increase and track the difference of CSeq when the server is performing proxy authentication to next hop for calls
  • plenty of new features for IMS extensions
  • detailed list of additions is very long, duplicating the content here making no sense, therefore head to read the dedicated wiki page:

Project achievements during v4.2.0 development cycle

  • the development of the project has entered in the 14th year of activity
  • it is the 15th major release in the history of project (SER project went out first with v0.8.x)
  • the number of commits to master branch (thus not counting commits in the other branches) has exceeded 20 000, effort being estimated to over 250 man-years of code development by OpenHub
  • the project successfully organized the second edition of it dedicated event, Kamailio World, the next edition is planned for May 27-29, 2015 in Berlin, Germany
  • activity continued at high pace by a large development team, four of the new modules in this version were contributed by new developers and few other long standing contributors became official developers
  • there was also very rich participation to world wide events such as Fosdem, LinuxTag, Astricon, Cluecon, Elastix World, VoIP2Day, ITSPA, WebRTC Conference & Expo, WebRTC Summit, DevCon5

Downloading v4.2.0

You can download the tarball of the released sources at:

Binary packages for several distributions can be found at:

Packages will be uploaded as soon as they are built by developers (Debian and Ubuntu debs as well as RPMs for Centos, RedHat, Fedora and OpenSUSE) or submitted by community for other operating systems.

A step by step installation tutorial is available at:


Useful links:

Many thanks to those contributing with code, helping testing or advocating the project!
We are looking forward to meeting many of you at events around the world and invite you to join the efforts to improve Kamailio!


Note: Kamailio is the new name of OpenSER project, name changed on July 28, 2008, due to trademark issues. First version under Kamailio name was 1.4.0. Older versions continued to use OpenSER name. Project site and SVN repository on SourceForge.net still use the old name OpenSER. Source code since release 3.0.0 (when the merge of source code trees of Kamailio and SER was completed) is hosted on GIT repository at http://sip-router.org. Starting with version 4.0.0, SER has been absorbed in Kamailio flavour, which became the default distribution of the project.