Group chat now available in Linphone!

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For many years, Linphone has been one of the most active communication software in the open source world. Originally focused on voice, additional functionalities were rapidly added, like video, instant messaging (IM) and presence.

Over the past year, most of our internal development resources have been dedicated to the big challenge of developing Linphone’s own implementation of group Instant Messaging.

The whole Linphone team is now delighted to offer the first entirely SIP-based open source solution for multi-participant Instant Messaging.

New Releases of LINPHONE 4.0 for iOS and Android

The new versions of Linphone for iOS and Android offer the following group chat features :

  • multi-participant groups with admins
  • support for multi-device per participant
  • file sharing for most types of content
  • intelligent search bar for an easy selection of participants
  • intuitive message delivery status
  • clear notifications of group events

In addition, this release benefits from Linphone’s new JAVA/JNI wrapper, which is now automatically generated from liblinphone C API.

> Download for free the latest version of Linphone 4 on Google Play or on the App Store.
> Contact if you are interested in integrating group chat features in your VoIP project.

The first SIP-BASED open source solution for group IM

The Session Initiation Protocol (SIP) has been used widely for years for audio and video calls. As a signaling protocol for creating, modifying and terminating multimedia sessions with one or more participants, it actually brings everything needed to efficiently develop IM and group IM solutions.

Thus, we chose to capitalize on our working and robust client & server implementation of one-to-one messaging on top of SIP, and to make use of existing IETF RFCs and GSMA RCS recommandations for group chat.

> To know more about our SIP-based implementation for group IM, click here.

A new server component: FLEXISIP conference server

In order to bring group chat features, Flexisip Conference Server has joined the Flexisip server suite, in addition to the existing Proxy and Presence servers. This entirely SIP-based conference server is in charge of the management of groups, participants' devices and group events notifications.

Flexisip has become a complete, modular and scalable SIP server suite that can be deployed in cluster mode for high availability and scalability.

The free SIP service is running with Flexisip and enables users of Linphone accounts to start enjoying group chat functionality.

For customers who already have their own SIP infrastructure, it is also possible to deploy Flexisip Conference Server into an existing SIP network running with third party SIP servers, provided that some technical conditions are met. Please consult our Wiki article for more information.

What’s next?

+ End-to-end encryption for group IM:

We are currently working on Linphone Instant Message Encryption (LIME) Protocol to implement parts of the Signal protocol, allowing users to privately and asynchronously exchange messages.

Within a few months, LIMEv2 will bring two major security benefits for Instant Messaging users :
end-to-end encryption, which means that no one except the senders and receivers can read the shared content, not even the server component between them.
perfect forward secrecy, that ensures that encrypted messages cannot be decrypted by a third party, should even one single key be compromised in the future.

+ Audio and video conferences:

Software's design is ready to implement server-based multi-participant audio and video conferences in the future.

+ Group chat feature in Linphone desktop:

Whereas multi-participant IM has only been added to Linphone iOS and Android versions for now, we aim at integrating it in Linphone for desktop in the medium term.