Flexisip 2.4 Release is Now Available!

We’re excited to announce the official release of Flexisip 2.4. This version brings numerous functional and technical improvements designed to simplify administration and enhance the user experience.

Bidirectional Calling with Third-Party Domains

The SIP Bridge (B2BUA) has evolved and now supports incoming calls from external domains such as third-party SIP domains, PSTN networks, or virtual numbers — in addition to already supporting outgoing calls. Thanks to this update, calls between Flexisip and third-party domains can now flow in both directions (incoming and outgoing).
User account management has also been optimized: the B2BUA can now dynamically retrieve gateway accounts from a database, replacing the old method of using text file configuration.

This feature allows integrators looking to connect external telephony services to their Flexisip infrastructure to maintain a clean, centralized architecture.

👉 Read the dedicated article for more information.

Proxy / NAT Helper: RFC 5626 Compliance

Flexisip introduces a new NAT routing strategy based on the flow-token mechanism, in compliance with RFC 5626.
This improvement enables:

• Better handling of persistent connections;
• More reliable signaling through NAT routers;
• Increased compliance with modern SIP standards.

👉 Learn more about RFC 5626.

Time Unit Configuration

You can now specify a time unit (ms, s, min, h, d, m, y) for all duration-related parameters in the configuration file. No more manual unit conversions — you can now directly write values like `30min` or `1y`, reducing the risk of errors.

Improved RTP/RTCP Port Management

The SIP Bridge (B2BUA) and conference servers now support new parameters (`audio` and `video port`) to precisely define the port ranges used for media traffic (RTP/RTCP). This enhances firewall compatibility and simplifies deployment in secured environments.

Configurable Conference Duration

A new audio parameter allows setting a maximum duration for incoming calls on the conference server. This ensures that calls exceeding a certain time limit are automatically terminated.

New Supported Environment

Flexisip 2.4 is now compatible with Ubuntu 24.04, staying aligned with the latest Linux OS versions.