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BigBlueButton

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Velocity6.3

Open-source web conferencing system for online learning

bigbluebutton.org ↗

BigBlueButton 4.0 enters release candidate with LiveKit fully replacing the legacy audio stack.

video-conferencingopen-sourcelivekit-migrationmobilewebrtc
◆Current state
BigBlueButton is in its final stretch to 4.0 GA, with three release candidates shipping in September 2026. The 4.0 release is a near-complete architectural rebuild: LiveKit has replaced SIP.js and mediasoup as the default media transport, BlockNote replaced the old shared notes engine, and the mobile layout was overhauled. RC2 shipped security fixes for a cross-meeting presentation injection vulnerability, urging immediate admin updates.
◆Where it's heading
The LiveKit migration that began in 3.x security patches has culminated in rc.1's 'LiveKit as audio state source' refactor — the legacy audio path is gone. Multi-room sessions with membership-based tokens and automatic token refresh enable scenarios (breakout listen-in, large conferences) that the old bridge couldn't cleanly support. A 4.0 GA release is imminent given the RC cadence.
◆Prediction
4.0 GA will ship within 2-3 weeks based on the RC pace. Post-GA focus will shift to hardening the LiveKit multi-room session model and expanding BlockNote capabilities (Markdown export landed in beta.4; more collaborative editing features likely next). The successful migration may influence other open-source video conferencing projects still running legacy SFU stacks.

◆Recent moves

  1. 4d ago

    BigBlueButton 4.0-rc.3: LiveKit resilience hardening, configurable whiteboard zoom

    Final stabilization pass before GA: in-depth LiveKit reconnection and resilience hardening, plus configurable whiteboard wheel zoom behavior (restoring the pre-4.0 direct wheel-zoom option for users who preferred it). The scope signals confidence in the core 4.0 feature set with remaining work focused on edge-case resilience.

    View source ↗
  2. 5d ago

    BigBlueButton 4.0-rc.2: security fixes — update immediately

    Security-only release fixing at least two vulnerabilities including cross-meeting presentation injection via an unbound upload token. Administrators are urged to update immediately — this is the second RC precisely because of security debt found during pre-GA review.

    View source ↗
  3. 14d ago

    BigBlueButton 4.0-rc.1: LiveKit becomes sole audio source, multi-room sessions land

    ⚡ SPARK

    The first release candidate for 4.0 completes the LiveKit architecture migration: LiveKit is now the sole audio state source, replacing the legacy FreeSWITCH/mediasoup path entirely. Multi-room sessions with membership-based token model and automatic refresh, plus breakout listen-in parity with the legacy stack, make the 4.0 architecture functionally complete.

    View source ↗
  4. 1mo ago

    BigBlueButton 4.0-beta.5: mobile layout rebuilt, dark mode auto-switch, audio settings

    Mobile layout overhauled with paginated webcams, compact bars, responsive dialogs, and side-by-side camera and presentation in landscape. Also adds automatic dark/light mode switching via prefers-color-scheme and a dedicated Audio settings tab. Significant UX improvement for the mobile use case that was visually broken in earlier 4.0 betas.

    View source ↗
  5. 1mo ago

    BigBlueButton 4.0-beta.4: LiveKit default (SIP.js removed), BlockNote default, Java 21

    ⚡ SPARK

    Beta.4 defaults to LiveKit for all audio (SIP.js bridge removed) and BlockNote for shared notes (with Markdown export), and upgrades to Java 21. This is the beta where 4.0 became irreversible — after this release there is no legacy audio path and no old notes engine to fall back to.

    View source ↗
  6. 3mo ago

    BigBlueButton 4.0-beta.3: Unified layout default, WASM audio processor, user search

    Layout System revamp defaults to the Unified layout with refined camera sorting, pagination, and a new multi-functional mode with dual sidebar panels. Adds a WASM-based audio processor running on the mic stream and user search in the user list. Substantial UI and audio quality improvements landing ahead of the later betas.

    View source ↗