Kamailio SIP Server v6.1.0 Released: A Major Leap Forward for Open-Source VoIP Infrastructure

Kamailio SIP Server v6.1.0 Released: A Major Leap Forward for Open-Source VoIP Infrastructure

February 18, 2026 — The Kamailio project has officially released version 6.1.0 of its widely deployed open-source SIP server, marking another significant milestone in the project’s nearly 25-year history.

This major release introduces a substantial set of new features, four brand-new modules, deep improvements to existing components, and enhanced platform support — reaffirming Kamailio’s position as one of the most capable and actively maintained SIP platforms available today.

What Is Kamailio?

Kamailio is a high-performance, open-source SIP (Session Initiation Protocol) server used globally by telecommunications carriers, VoIP service providers, enterprises, and cloud communications platforms. It handles SIP signaling for voice, video, and messaging services, and is known for its modularity, extensibility, and ability to scale to millions of simultaneous connections.

Four New Modules

Among the headline additions in v6.1.0 are four entirely new modules, each targeting distinct use cases:

auth_arnacon — Provides ENS-based (Ethereum Name Service) cryptographic authentication, opening the door for decentralized identity verification in SIP communications.
auth_web3 — Delivers blockchain-based authentication with integrated ENS support, reflecting growing interest in Web3 identity frameworks within telecommunications.
peerstate — Tracks registration and call states for peers, enabling more granular monitoring and control of connected endpoints.
ptimer — Allows configuration route blocks to be executed on a precise-timer basis, enabling fine-grained scheduling logic directly within Kamailio’s configuration scripting environment.

Key Highlights

Beyond the new modules, v6.1.0 delivers a wide range of enhancements across the platform:

TLS and Security

Multi-threaded TLS operations can now be enabled, improving performance for deployments with heavy encrypted traffic. Administrators can also configure Kamailio to log TLS session keys and optionally send them to a remote peer — a capability valuable for lawful interception and troubleshooting encrypted sessions. Additionally, multiple TLS connections with different TLS domain configurations can now be established to the same host and port target, offering greater flexibility in complex routing environments. SHA-512 and SHA-512-256 are now supported for user authentication hashing, providing stronger cryptographic options alongside existing algorithms.

Recording and Media

New functions have been added to facilitate SIPREC (SIP Recording) workflows in combination with RTPEngine, streamlining the implementation of call recording architectures. The sipdump module has also been enhanced with the ability to specify file age using time expressions, improving log management for high-traffic deployments.

Routing and Transaction Control

A new dispatcher algorithm combines round-robin and priority-based routing, giving operators more nuanced control over load distribution. Options have been added to apply SIP request processing changes during transaction route branch execution, and to automatically apply changes before a transaction is created. Transaction UAC functions and RPC commands for fine-grained control of locally initiated calls are also included.

Runtime Management

RPC commands now allow administrators to get and, when enabled, set module parameters at runtime — reducing the need to restart the server for configuration adjustments. An internal hash table for DMQ (Distributed Message Queue) replication within the rtpengine module improves clustering behavior.

Developer and Configuration Enhancements

A new generic core parameter definition framework simplifies module development and configuration. Per-via-branch flags can now be stored in SIP message parameters and retrieved later, supporting more complex routing logic. Binary message bodies can be set via hexadecimal-encoded parameters. New variables and transformations have been added throughout the system, and the KEMI (Kamailio Embedded Interface) framework — which allows scripting in languages such as Python, JavaScript, Ruby, and Lua — has received updates as well, including support for larger JavaScript files in the app_jsdt module.

Platform and Infrastructure Improvements

Version 6.1.0 brings improved support for the ARM64 (AArch64) architecture, leveraging stdatomic and pthread locking for more reliable behavior on modern ARM-based servers and edge devices. Additional improvements include sentinel support for the db_redis module, millisecond precision for CDR-at-once accounting, the ability to check whether a connection is alive by remote address and port from the configuration, and basic JSONRPC support for kamcmd.

Project Milestones

The v6.1.0 release cycle saw approximately 1,500 commits to the master branch from more than 50 individual contributors, bringing the project’s total commit count to over 40,000. The Kamailio project is approaching 25 years of continuous development and this marks its 28th public major release since the original SER (SIP Express Router) project launched with version 0.8.x.

The 14th edition of Kamailio World, the project’s annual conference, is scheduled for May 7–8, 2026, in Berlin, Germany.

Availability

Kamailio v6.1.0 source tarballs are available at the official project website. Binary packages for Debian, Ubuntu, CentOS, Red Hat, Fedora, and OpenSUSE are being rolled out as they are built by the development team and community contributors.

Source: https://www.kamailio.org/pub/kamailio/latest-6.1.x/src/
Documentation: https://www.kamailio.org/docs/modules/6.1.x/
Migration Guide (6.0.x → 6.1.0): https://www.kamailio.org/wikidocs/install/upgrade/6.0.x-to-6.1.0/

Kamailio is a free and open-source project. The development community welcomes contributions, testing feedback, and financial support via the project’s donations page.

Kamailio SIP Server v6.1.0 Released: A Major Leap Forward for Open-Source VoIP Infrastructure. This major release introduces a substantial set of new features, four brand-new modules, deep improvements to existing components, and enhanced platform support — reaffirming Kamailio's position as one of the most capable and actively maintained SIP platforms available today.