Kamailio v4.0On March 11, 2013, Kamailio (SER) SIP Server v4.0.0 has been released – this is a special major release, shifting up the first digit in versioning number.

Kamailio version 4.0 brings a lot of improvements and new features to the leading Open Source SIP Server.  Here’s a few examples of the core new features in this major release (and the reasons we’re releasing a 4.x series upgrade):

  • End of Kamailio – SER integration: In the 3.x release series, Kamailio and SER shared the core source code, but there was duplicated modules and different database structures. Now the project is back to one set of modules, with all the duplicated modules having been integrated. There’s now one set of modules, not three.
  • New transport layer: Starting with this release, Kamailio supports the WebSocket transport layer (both plain and secure), in addition to UDP, TCP, TLS and SCTP. WebSocket support (as outlined in an IETF draft with one of the Kamailio developers as co-author) allow modern Web browsers and Javascript SIP stacks to place calls and chat using SIP for signaling.
  • Kamailio is the default application name (aka, default flavour), what the project is packaging. SER can be built manually, and the “SER” flavour is kept for historical and maintenance reasons.

Overview of new features in v4.0.0

(for more details see the wiki page)

  • Support of the transport layer requirements to use SIP and MSRP for WebRTC via the websocket module
  • Availability of many IMS extensions, making Kamailio one of the most evolved Open Source IMS platforms out there
  • Over ten modules, earlier part of SER flavour only, are now available for Kamailio users
  • Fifteen brand new modules: cdp, cdp_avp, corex, dialog_ng, ims_authims_icscf, ims_isc, ims_qosims_registrar_pcscf, ims_registrar_scscf, ims_usrloc_pcscf, ims_usrloc_scscf, outbound, websocket, xhttp_pi
  • Improvements and new features in over fifty modules that were shipped in previous major release
  • New internal libraries and functionalities in the core
  • New config variables and transformations
  • Substantial development related to SIP Outbound extensions, being nearly to full implementation
  • Embedded web provisioning interface
  • Option to remove NATed location records that don’t respond to UDP SIP keepalives
  • DNSSEC support as a compile time option
  • HEPv3 support for distributed SIP capturing and monitoring with Homer SIPcapture
  • Improved support for embedded Linux systems
  • 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 v4.0.0 development cycle:

  • Project participation with speeches, exhibition booth or workshops at various events, including FOSDEM, LinuxTag, Astricon, CeBIT, Call Center World, UC Expo
  • According to Ohloh project, during the past year:
    • We had a significant increase in development activity (39%)
    • The project maintains itself as one of the largest open-source teams in the world, and is in the top 2% of all project teams on Ohloh
    • Estimated development effort so far is over 11.5 millions USD, equivalent of 211 person-years
  • Kamailio World ConferenceLaunch of the first dedicated public event for the project – Kamailio World Conference – to take place during April 16-17, 2013, in Berlin, Germany
    • the project had a continuous growth over the past years, offering the framework to build solutions for a vast set of requirements, from operator platforms to interconnect carriers, rich communication services (with instant messaging, presence file transfer, desktop sharing, a.s.o.), WebRTC providers or mobile operators deploying IMS core infrastructure.
    • speakers and agenda are lined up, the event offers a real opportunity to get in contact with those building large IP telephony (VoIP) platforms and Rich Communication Services (RCS). More details at:

Important notes:

  • Default flavour is kamailio, there is no more need to set the flavour in make configuration when targeting to install Kamailio from sources

    • flavour system is kept for people willing to build the application under SER name, to ease the upgrade of existing deployments
  • A step by step installation tutorial is available at:

DownloadsDownloading v4.0.0:

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.


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 Kamailio World Conference!


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.